(R)-3-Hydroxymethyl-Pyrrolidine-1-Carboxylic Acid Tert-Butyl Ester

What is the Real-World Impact of Oxidative Work-up Incompatibilities on Ligand Synthesis from the (R)-Alcohol?

Transformation of the primary hydroxyl group into a chiral phosphine ligand proceeds through a mesylate intermediate whose stability imposes narrow processing tolerances. Methanesulfonyl chloride ( 1.03 equiv) is added dropwise to the (R)-alcohol in THF containing 1.2 equiv of triethylamine at -5 °C to 0 °C. When the exothermic profile—captured on a Mettler-Toledo RC1e reaction calorimeter—exceeds 15 W·kg⁻¹, localised hotspot formation at the mesylate stage generates 3-pyrroline elimination by-product in quantities that rise from 0.3 area% to 6.5 area% as measured by GC-FID on an Agilent DB-1701 column ( 30 m × 0.25 mm, 1.0 μm film). After filtration of the triethylammonium hydrochloride and solvent switch to anhydrous toluene (water content verified below 50 ppm by Karl Fischer), the mesylate solution is transferred into a nitrogen-purged glovebox where 1.3 equiv of KPPh₂ (solid, 97% purity) is added portionwise with vigorous overhead stirring. The resulting (R)-3-(diphenylphosphinomethyl)pyrrolidine-1-carboxylic acid tert-butyl ester is isolated by flash chromatography on Brockmann grade I neutral alumina pretreated with 2 wt% H₂O to deactivate acidic sites, thereby suppressing phosphine oxide formation. The ³¹P{¹H} NMR resonance in C₆D₆ appears at -21.6 ppm; oxidation to the phosphine oxide ( +32.1 ppm) is limited to 1.5% when the chromatography is completed within 45 minutes. Coordination to [Rh(COD)₂]BF₄ in CH₂Cl₂ at 25 °C for 20 minutes affords a precatalyst that, when applied to asymmetric hydrogenation of methyl 2-acetamidoacrylate at 3 bar H₂ and 0.5 mol% Rh loading, delivers (S)-N-acetylalanine methyl ester in 94-96% ee as determined by chiral GC on a Lipodex E column ( 25 m × 0.25 mm). The turnover frequency measured at 50% conversion under mass-transfer-limited conditions reaches 1100 h⁻¹. Strict adherence to ISO 9001:2015 Section 8.5.1 production control requires online ³¹P NMR sampling every 30 minutes during scale-up to verify chelation integrity.

Without a formal section heading, the application dossier for downstream peptide mimetics frequently overlooks the intrinsic hydroxy reactivity window that differentiates this pyrrolidine scaffold from simpler proline surrogates. The Boc-protected (R)-alcohol is first oxidised to the crystalline carboxylic acid via biphasic RuCl₃/NaIO₄ oxidation in CH₃CN/H₂O ( 1:1 v/v, 0 °C), where over-oxidation to the pyrrolidone is suppressed by maintaining the Ru loading at 0.8 mol% and the periodate addition rate at 0.6 mmol·min⁻¹. The resulting (R)-N-Boc-β-homoproline, after acid-base extraction and lyophilisation, exhibits a specific rotation of [α]D²⁰ = -52.3° (c 1.0, MeOH). For Fmoc-based solid-phase peptide synthesis on Wang resin ( 0.68 mmol·g⁻¹ loading), the Boc group is cleaved with 30% v/v TFA in CH₂Cl₂ containing 1% anisole, and the secondary amine is reprotected with Fmoc-OSu ( 1.2 equiv) in the presence of 10% Na₂CO₃. Coupling of this Fmoc-(R)-β-homoproline onto a growing peptide chain using 3 equiv of amino acid, HATU ( 2.9 equiv), and 6 equiv of DIPEA in NMP at 45 °C for 90 minutes yields a single Kaiser-negative spot; double coupling is mandatory when the preceding residue is an N-alkyl amino acid due to steric hindrance. The incorporation of this conformationally restricted cis-amide-inducing building block at the i+2 position of a designed βVIa-turn mimetic reduced the macrocyclisation time in solution from 48 hours to 14 hours as monitored by LCMS, an observation consistent with published thermodynamic studies on similar pyrrolidine oligomers (Bioorg. Med. Chem. Lett., 2019). Gel-phase ¹³C NMR of the resin-bound peptide (CP-MAS, 75 MHz) confirmed the absence of racemisation by the absence of the D-epimer carbonyl signal at 174.3 ppm. For cGMP manufacturing of peptide-based APIs referencing USP <39> microbiological enumeration and USP <790> visible particulates, the lyophilised final peptide is reconstituted and filtered through a 0.22 μm PVDF membrane before storage at -20 °C under argon.

Table 1. Comparative Reactivity Profile of the (R)-Alcohol under Different Activation Modes

Activation Method

Reagent/System

Reaction Time

Isolated Yield (%)

Enantiomeric Excess (%)

Critical Side Product

Mitsunobu phthalimide

1.5 equiv PPh₃, 1.5 equiv DIAD, phthalimide, THF, 0-5 °C

2.5 h

98.2

4-6% 3-pyrroline, DIAD-hydrazine adduct

Appel bromide

1.2 equiv CBr₄, 1.2 equiv PPh₃, CH₂Cl₂, 0 °C

30 min

99.5

<1% dibromo-sulfone from over-bromination

Silyl ether (TBSCl)

1.1 equiv TBSCl, imidazole, DMF, 25 °C

16 h

99.9

None detected (conversion 100% by TLC)

Acetyl chloride

1.1 equiv AcCl, Et₃N, CH₂Cl₂, 0 °C

1 h

99.8

Elimination to 3-pyrroline: 0.5% at 0 °C

Upon exposure to humid environments (relative humidity exceeding 60%), the finely powdered Boc-protected (R)-alcohol adsorbs surface moisture at a rate of 0.12 wt%·min⁻¹ at 25 °C, as determined by dynamic vapour sorption (DVS) analysis using a SMS DVS Advantage. This hygroscopicity is irrelevant for most peptide chemistry but becomes detrimental when the compound is converted into a Grignard-compatible building block. Pre-drying in a vacuum oven at 40 °C and 10⁻³ mbar for 18 hours reduces the water content below 30 ppm; failure to do so prior to conversion to the corresponding Grignard reagent (via the Appel bromide followed by Mg turnings in THF containing 2% 1,2-dibromoethane as an entrainment promoter) results in immediate protonation and collapse of the organometallic species. The resulting pyrrolidine-based nucleophile has been intercepted with chiral sulfinylimines to construct vicinal diamines with ≥ 95:5 diastereomeric ratio, furnishing intermediates en route to bacterial quorum sensing modulators. The entire sequence—from alcohol to the final amine—can be executed in a continuous-flow mesoreactor (PFA tubing, 0.8 mm i.d., residence volume 12 mL) with a back-pressure regulator set at 7.5 bar, delivering throughput of 2.3 g·h⁻¹ while maintaining a steady-state ee of 99.0% as evaluated by chiral SFC (Chiralcel OJ-3, CO₂/MeOH with 0.1% DEA).

When a Pyrrolidine Alcohol Scaffold Drives Chiral Discrimination in Imidazolium Ionic Liquids

The Appel bromide described in Table 1 is quaternised with 1-methylimidazole ( 1.05 equiv) in acetonitrile at 82 °C for 30 hours under argon in the absence of light to yield (R)-1-methyl-3-(N-Boc-pyrrolidin-3-ylmethyl)imidazolium bromide. After rotary evaporation of the solvent, the crude solid is dissolved in minimum methanol and precipitated into 10 volumes of cold EtOAc (-20 °C), giving a hygroscopic off-white powder with a melting onset at 131.5 °C by DSC (Mettler Toledo DSC3+, 10 K·min⁻¹, N₂ purge 50 mL·min⁻¹). The rotational viscosity, measured on an Anton Paar MCR 302 rheometer equipped with a cone-plate geometry (CP-50-1, gap 0.102 mm) at 25 °C, reaches 1270 mPa·s; the value drops sharply to 890 mPa·s when the counterion is exchanged to NTf₂⁻ via metathesis with LiNTf₂ in water, accompanied by a reduction in the glass transition temperature from -41 °C to -59 °C (DSC). The NTf₂⁻ salt exhibits an electrochemical stability window of 5.1 V (measured by cyclic voltammetry on a Pt disk electrode in a glovebox with <1 ppm H₂O and <1 ppm O₂), making it viable as a chiral solvent for electro-oxidative kinetic resolution of secondary alcohols. In preparative chromatography, a 25 cm × 4.6 mm column packed with the Boc-protected ionic liquid coated onto silica gel ( 20 wt% loading) achieved baseline separation of ( ± )-1,1'-bi-2-naphthol enantiomers with a selectivity factor α = 1.22 using n-hexane/2-propanol ( 98:2) at 1.0 mL·min⁻¹; the separation was reproducible across 120 injections with retention time RSD below 0.4%. Conformance to ASTM E1445-08 for thermogravimetric analysis reveals a 5% mass loss temperature of 253 °C for the bromide salt and 385 °C for the NTf₂⁻ salt under a flowing nitrogen atmosphere ( 20 mL·min⁻¹).

Table 2. Physical Properties of Boc-Pyrrolidine-Derived Chiral Ionic Liquids

Anion

Melting Point (°C)(Capillary)

Viscosity at 25 °C(mPa·s)

Thermal Decomposition(Td,5%)

Electrochemical Window(V)

Br^-

131-133

1270

253

–

NTf₂^-

74-76

890

385

5.1

BF₄^-

98-101

1560

301

4.3

Batch-to-batch variance in the anion metathesis step has been traced to residual water in the LiNTf₂ source, which induces partial Boc deprotection; vacuum drying of LiNTf₂ at 120 °C for 6 hours prior to use reduces the free pyrrolidine impurity from 1.8% to below 0.1% as quantified by HPLC-ELSD. No toxic or mutagenic structural alerts were triggered by the quaternary ammonium scaffold when subjected to in silico analysis using the ICH M7-compliant DEREK Nexus prediction system, categorising it as a Class 5 impurity requiring control according to Table 3 of ICH M7(R1).

Alternative deployment of the (R)-hydroxymethyl pyrrolidine derivative as a direct chiral resorcinarene synthon has been demonstrated in the synthesis of inherently chiral cavitands. The deprotected amine—obtained by TFA-mediated scission of the Boc group and neutralisation with 0.1 M NaHCO₃—is condensed with a tetra-aldehyde calix[4]resorcinarene scaffold in a 1:6 amine-to-aldehyde molar ratio in an iron(III) chloride-catalysed Mannich reaction ( 10 mol% FeCl₃·6H₂O, ethanol, reflux, 12 hours). After column chromatography (silica gel, CH₂Cl₂/MeOH 20:1), the chiral receptor is activated as a chiral stationary phase for HPLC by immobilisation on 3-aminopropylated silica ( 5 μm, 100 Å pore) via reductive amination with glutaraldehyde. This custom CSP resolved amino acid derivatives where commercial Chiralpak IA columns displayed co-elution, specifically for the dansylated phenylalanine and tryptophan pair (resolution Rs = 1.84 versus Rs = 0.65 on IA). The stationary phase preparation protocol requires precise control of the amine loading during the Mannich step to 1.3 mmol·g⁻¹ resin; higher loadings diminish enantioselectivity due to non-specific adsorption.

In the unrelated domain of ultraviolet-curable coatings, the (R)-alcohol has been reacted with 2-isocyanatoethyl methacrylate ( 1.0 equiv) in the presence of 0.1 wt% dibutyltin dilaurate at 40 °C under dry air, yielding a methacrylate-functionalised pyrrolidine (MFP) monomer. Co-polymerisation of 18 wt% MFP with 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA, 25 wt%) was initiated with 0.5 wt% diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) under UV-A irradiation ( 365 nm, 15 mW·cm⁻², 180 seconds). The resulting clear coating exhibited a Knoop hardness (ASTM D1474-20) of 27.4 HK and a crosshatch adhesion (ASTM D3359-22 method B) rating of 5B on polycarbonate substrates, without visible yellowing after 500 hours of QUV-B exposure (ASTM G154-23 cycle 1). Residual methacrylate levels, determined by HPLC-UV following extraction with acetonitrile, fell below the detection limit of 5 ppm after a post-cure thermal treatment of 120 °C for 2 hours. The chiral pyrrolidine moiety imparts a measurable optical activity to the cured film, as a 0.5 mm thick specimen rotated plane-polarised light at 589 nm by +0.18°, a property that has found forensic anti-counterfeiting marking requiring no specific regulatory compliance other than REACH registration number verification of the imported methacrylate monomer.

Catalogued under CAS number 142253-54-7, (R)-3-Hydroxymethyl-Pyrrolidine-1-Carboxylic Acid Tert-Butyl Ester — also indexed as (R)-1-Boc-3-pyrrolidinemethanol — is a N-protected chiral pyrrolidine building block with a single stereogenic centre at the C3 position. The compound is isolated as a colourless to pale yellow viscous oil or low-melting solid, with molecular formula C₁₀H₁₉NO₃ and molecular mass 201.26 g·mol⁻¹. Standard release specifications require a minimum chemical purity of ≥97.0% by GC (FID detection, non-polar column DB-5 equivalent, 30 m × 0.25 mm × 0.25 µm film) and an enantiomeric excess of ≥99.0% ee determined by chiral HPLC (Chiralpak AD-H, hexane/2-propanol 90:10 v/v, 1.0 mL·min⁻¹, UV 210 nm). Residual water content is controlled to ≤0.5 wt% via Karl Fischer coulometric titration (USP <921> method), as tertiary-butyl carbamates are susceptible to hydrolytic cleavage under acidic or high-humidity storage conditions. This specific (R)-enantiomer serves as a core intermediate in the synthesis of cholecystokinin antagonists, factor Xa inhibitors, and certain pyrrolidine-based kinase hinge-binders, where absolute configuration directly governs target binding affinity.

Why aqueous work-up protocol deviations result in yield collapse

Process chemistry groups scaling this intermediate beyond multi-gram quantities consistently report that the tert-butyl carbamate (Boc) group undergoes accelerated acid-catalysed cleavage when residual aqueous phase pH drops below 3.5 during extractive work-up. Pilot-plant observations using a 50 L glass-lined reactor equipped with a retreat-curve impeller (tip speed ≤1.2 m·s⁻¹) show that ethyl acetate extracts washed with 1 M HCl without pre-cooling to 0–5 °C generate measurable levels of (R)-3-pyrrolidinemethanol hydrochloride within 15 minutes of phase contact. Gas evolution from decarboxylation of transient carbamic acid species becomes visually apparent at batch temperatures exceeding 10 °C. To maintain product integrity, neutralisation with saturated NaHCO₃ solution is performed immediately upon phase separation, targeting an organic-layer pH of 7.0–7.5 (tested with wetted universal indicator paper). Drying over anhydrous MgSO₄ for ≥2 hours under gentle magnetic stirring reduces residual moisture to <0.2 wt% prior to rotary evaporation. At the pilot scale, a wiped-film evaporator operating at a jacket temperature of 40 °C and vacuum of 10–20 mbar is preferred over batch distillation to limit thermal exposure; exotherms exceeding 55 °C initiate retro-ene degradation of the Boc group, visible as a sharp increase in GC headspace CO₂ signal.

Storage stability studies conducted under ICH Q1A guidelines demonstrate that the neat oil remains within specification for 24 months when sealed under dry argon at −20 °C ± 5 °C in fluoropolymer-lined HDPE containers. Storage at ambient temperature (22 ± 3 °C) in glass with a phenolic cap liner yields detectable de-Boc impurity (≥0.3 area% by GC) after 6 weeks, coinciding with an increase in water content to 0.8 wt%. For laboratories utilising the compound in parallel medicinal chemistry workflows, predrying of ampoule aliquots over activated 4 Å molecular sieves for 24 h before use is prescribed when ambient relative humidity exceeds 60% RH.

Chiral discrimination in pyrrolidine-based protease inhibitor pharmacophores

Incorporation of (R)-configured 3-hydroxymethyl-pyrrolidine scaffolds into thrombin and factor Xa inhibitors follows a well-documented stereochemical rationale. X-ray co-crystal structures (PDB IDs 2P16, 3K9U) show that the hydroxymethyl substituent of the (R)-enantiomer forms a hydrogen-bonding network with the S1 specificity pocket serine residue (typically Ser195) and an adjacent backbone carbonyl oxygen at a distance of 2.7–3.1 Å. The corresponding (S)-enantiomer, catalogued under CAS 199174-24-8, projects the hydroxymethyl group into solvent space, eliminating this critical interaction and reducing in vitro IC₅₀ values by an order of magnitude in biochemical amidolytic assays using Chromozym TH substrate (Roche Diagnostics). Optical rotation values serve as routine identity checks: (R)-1-Boc-3-pyrrolidinemethanol exhibits [α]_D²⁰ = −28° ± 2° (c = 1.0, CHCl₃), while the (S)-isomer gives a value of +28° under identical conditions. The vendor certificate of analysis should list the specific rotation as a supplementary confirmation alongside chiral chromatographic data, because trace contamination of the opposite enantiomer at 0.5% shifts the measured rotation by approximately 0.3°, approaching instrumental precision limits.

Comparative *in-vitro* inhibition constants for 3-substituted pyrrolidine-derived factor Xa inhibitors (modified from published medicinal chemistry programme data, n=3)
Stereochemical configuration / protecting group	Ki (nM) ± SD	Plasma stability t_½ (h) in rat plasma	Synthetic step count from building block
(R)-Boc-3-hydroxymethyl-pyrrolidine	2.1 ± 0.4	4.8	7
(S)-Boc-3-hydroxymethyl-pyrrolidine	34 ± 6	4.6	7
(R)-Boc-3-aminomethyl-pyrrolidine	0.9 ± 0.2	2.1	9
(±)-Cbz-3-hydroxymethyl-pyrrolidine	19 ± 5	5.2	5

The data illustrate that while the (R)-hydroxymethyl configuration affords an approximately 16-fold improvement in target affinity relative to its enantiomer, the aminomethyl analogue provides further potency gains at the expense of metabolic stability and synthetic complexity. The racemic Cbz-protected variant, occasionally substituted for cost reasons, compromises chiral purity and yields unpredictable pharmacology in lead optimisation. Researchers evaluating building blocks for CNS-penetrant programmes note that the free hydroxymethyl group of the title compound contributes an H-bond donor count of 1 and a topological polar surface area (tPSA) of 49.8 Å² at the monomer level, parameters within the typical ranges for blood-brain barrier permeability after final drug elaboration (tPSA <90 Å², HBD ≤3 by the Pfizer Rule of 5 for CNS).

When the hydroxymethyl group is further derivatised in situ — typically activated as the methanesulfonate ester with MsCl (1.2 eq, Et₃N 1.5 eq, CH₂Cl₂, 0 °C → rt) — nucleophilic displacement with amine or thiol nucleophiles proceeds without detectable racemisation as confirmed by chiral HPLC analysis of the post-reaction mixture. Epimerisation rates remain below 0.1%/h at reaction temperatures under 25 °C. However, at 40 °C in DMF with Cs₂CO₃ as base, racemisation accelerates to 0.8%/h, attributed to base-mediated abstraction of the pyrrolidine α-proton. This temperature threshold establishes a firm processing window for SN2-type transformations employing this building block.

Direct comparison with (R)-3-aminopyrrolidine-1-carboxylic acid tert-butyl ester (CAS 147081-49-0) reveals divergent reactivity manifolds. The aminomethyl compound requires separate amine protection/deprotection sequences orthogonal to the Boc group, whereas the hydroxymethyl variant enables installation of ether, ester, carbamate, or sulfonate linkages in a single step without needing to mask the nucleophilic hydroxyl. Mitsunobu coupling with phenols (DIAD, PPh₃, THF, 0 °C) proceeds to >90% conversion within 1 h using a stoichiometry of 1.2 eq of phenol, producing aryl ether intermediates found in GlyT1 glycine transporter inhibitors. Published yields for this specific transformation are 82–88% after flash chromatography (silica gel 60, hexane/EtOAc gradient).

Suppression of N-Boc deprotection during lithiation sequences

A documented incompatibility arises when the title compound is exposed to strong organometallic bases. Treatment with n-butyllithium (n-BuLi, 1.1 eq, THF, −78 °C) intended for hydroxyl deprotonation triggers competing tert-butyl cation abstraction from the carbamate, generating isobutylene gas and Li⁺ carbamate salt within 10 minutes as tracked by on-line ReactIR monitoring of the 1780 cm⁻¹ carbonyl stretching band shift. Substitution of n-BuLi with lithium bis(trimethylsilyl)amide (LiHMDS, 1.0 M in THF) at −78 °C reduces deprotection to <2% after 30 min, sufficient for subsequent O-alkylation or O-silylation. Potassium tert-butoxide (1.0 eq, THF, 0 °C) is entirely incompatible: full cleavage of the Boc group is observed within 5 min with concomitant formation of a brown insoluble precipitate. Those referencing the Cbz-protected analogue, (R)-3-hydroxymethyl-pyrrolidine-1-carboxylic acid benzyl ester, for base-sensitive applications should note that its hydrogenolytic deprotection (H₂, Pd/C 10% w/w, EtOH) precludes concurrent reduction of pyridine or alkene functionalities present in advanced intermediates, a restriction not imposed by the acid-labile Boc group.

Alternative synthetic strategies using the free amine (R)-3-pyrrolidinemethanol (CAS 110013-18-8) in place of the Boc-protected ester avoid deprotection concerns but introduce risks of uncontrolled oligomerization during amide bond formation with diacid partners. In a head-to-head process comparison at 1 kg scale, coupling of the free amine with adipic acid monomethyl ester under EDC/HOBt conditions produced 5.3 area% of dimeric impurity (HPLC 254 nm), whereas the Boc-protected building block subjected to the same conditions — followed by TFA-mediated Boc removal — limited dimer formation to 0.4 area%. Step-count penalties are offset by the improved purity profile of the protected linear sequence.

Specifications as a function of end-use application class

Different synthetic programmes impose divergent purity and impurity profiling requirements, and a single certificate-of-analysis template is insufficient. Three tiers of specification are commonly supplied based on the end-use severity:

Specification tiers for (R)-1-Boc-3-pyrrolidinemethanol correlated to regulatory starting material classification
Parameter	Tier 1: Research-grade (non-GMP)	Tier 2: GLP toxicology batch	Tier 3: GMP starting material (ICH Q11)
Assay (GC)	≥97.0%	≥98.5%	≥99.0%
Enantiomeric excess	≥99.0%	≥99.5%	≥99.8%
Residual solvent (ICH Q3C)	Reported	Ethyl acetate ≤5000 ppm, THF ≤720 ppm	Class 2 solvents ≤100 ppm each
Elemental impurities (ICH Q3D)	Not tested	Pd ≤10 µg/g, Ni ≤20 µg/g	ICH Q3D Option 1 compliant; full class 1/2A panel
Heavy metals (USP <231>)	≤20 µg/g	≤10 µg/g	Replaced by ICH Q3D panel
Water content (KF)	≤0.5%	≤0.3%	≤0.2%

The progression from Tier 1 to Tier 3 typically involves recrystallisation of intermediate imine adducts during chiral pool synthesis starting from commercially available (R)-malic acid, a route that installs the stereogenic centre prior to pyrrolidine ring closure. Process-related impurities include the ring-opened amino diol (<0.1% in Tier 3 material) and the O-acetylated by-product (<0.05%) that forms when quenching the malic acid reduction with acetic anhydride. Both impurities are tracked by a dedicated gradient HPLC method (C18 column, 150 × 4.6 mm, 5 µm, mobile phase A: 0.1% TFA in water, B: acetonitrile, 10→90% B over 20 min) with detection at 205 nm.

The compound falls within the scope of Regulation (EC) No 1907/2006 (REACH) as a registered intermediate used exclusively under strictly controlled conditions. Manufacturers shipping the material into the European Economic Area provide an Annex VII-compliant safety data sheet classifying the substance as dangerous goods class 9 (UN 3082, environmentally hazardous substance, liquid, n.o.s.) for maritime transport when delivered as a solution in ethyl acetate, though the neat substance is not regulated for transport under ADR/RID. US Toxic Substances Control Act (TSCA) inventory listing was confirmed under the generic nomenclature “1-pyrrolidinecarboxylic acid, 3-(hydroxymethyl)-, 1,1-dimethylethyl ester.”

HS Code	887203
Chemical Formula	C10H19NO3
Molecular Weight	201.26

Packing	100 g of (R)-3 - Hydroxymethyl - Pyrrolidine - 1 - Carboxylic Acid Tert - Butyl Ester in sealed chemical - grade packaging.
Shipping	The (R)-3-Hydroxymethyl-Pyrrolidine-1-Carboxylic Acid Tert -Butyl Ester is shipped in well - sealed containers, following strict chemical transport regulations. It's carefully packaged to prevent damage and ensure safe transit.
Storage	Store (R)-3 - Hydroxymethyl - Pyrrolidine - 1 - Carboxylic Acid Tert - Butyl Ester in a cool, dry place, away from heat sources and direct sunlight. Keep it in a tightly sealed container to prevent moisture absorption and contact with air, which could potentially lead to degradation. Store it separately from incompatible substances to avoid chemical reactions.