3999-38-0

Basic information

• Product Name: Borane-2-picoline complex
• Synonyms: BORANE - 2-PICOLINE COMPLEX;2-methylpyridine borane;2-picoline borane;borane - 2-methylpyridine complex;Trihydro(2-methylpyridine)-boron;Borane - 2-Picoline Complex 2-Picoline Borane 2-Methylpyridine Borane;orane-2-picoline coMplex;(2-Methylpyridin-1-iuM-1-yl)trihydroborate
• CAS NO: 3999-38-0
• Molecular Formula: C₆H₁₀BN
• Molecular Weight: 106.96
• EINECS: 1312995-182-4
• Product Categories: B (Classes of Boron Compounds);Boranes;Reduction;Synthetic Organic Chemistry
• Mol File: 3999-38-0.mol
• Article Data: 10

Chemical Properties

• Melting Point: 48 °C
• Flash Point: 100°(212°F)
• Appearance: White/Solid
• Density: 1.297 g/mL at 25 °C
• Storage Temp.: 2-8°C
• Water Solubility: Slightly sol. in water, cyclohexane, very sol. in methanol, THF, diglyme, and benzene
• Sensitive: Moisture Sensitive
• CAS DataBase Reference: Borane-2-picoline complex(CAS DataBase Reference)
• NIST Chemistry Reference: Borane-2-picoline complex(3999-38-0)
• EPA Substance Registry System: Borane-2-picoline complex(3999-38-0)

Safety Data

• Hazard Codes: F,Xn,Xi
• Statements: 14/15-40-36/37/38-26
• Safety Statements: 36/37-43-26-36/37/38-14/15
• RIDADR: UN 3130 6.1(4.3) / PGII
• WGK Germany: 3
• HazardClass: 4.3
• PackingGroup: II
• Hazardous Substances Data: 3999-38-0(Hazardous Substances Data)

Usage

Uses

Different sources of media describe the Uses of 3999-38-0 differently. You can refer to the following data:
1. Environmentally benign reducing agent. Reactant for: Reductive amination. N-Benzyl-protection of amino acid derivatives by reductive alkylation. Reductive alkoxyamination.
2. Used as reactant for N-Benzyl-protection of amino acid derivatives by reductive alkylation, reductive alkoxyamination, as reducing agent for the labeling of oligosaccharides by reductive amination, synthesis of alkoxyamine derivatives, via reduction of oxime ethers, reductive amination reactions of C1-C10 aldehyde 2,4-dinitrophenylhydrazones, synthesis of various trifluoromethylated amino compounds and an alternative reagent for reductive aminations.

General Description

2-Methylpyridine borane complex is a nontoxic alternate to the reducing agent sodium cyanoborohydride.

InChI:InChI=1/C6H7N.BH3/c1-6-4-2-3-5-7-6;/h2-5H,1H3;1H3

Synthetic route

α-picoline (109-06-8) + sodium tetrahydroborate (16940-66-2) → 2-picoline borane complex (3999-38-0)

Conditions	Yield
With iodine In 1,2-dimethoxyethane byproducts: NaI, H2; addn. of stoichiometric amounts of I2 in DME to Na(BH4) (15-20% excess) and CH3C5H4N (7-10% excess), stirring for 3h, evapn., extn. with C6H6, evapn.;; dissolving in C6H6, pptn. with hexane;;	94%
With I2 In 1,2-dimethoxyethane byproducts: NaI, H2; addn. of stoichiometric amounts of I2 in DME to Na(BH4) (15-20% excess) and CH3C5H4N (7-10% excess), stirring for 3h, evapn., extn. with C6H6, evapn.;; dissolving in C6H6, pptn. with hexane;;	94%
With water; sodium hydrogencarbonate In tetrahydrofuran at 20℃; for 4h;	94%

α-picoline (109-06-8) + diborane (19287-45-7) → 2-picoline borane complex (3999-38-0)

Conditions	Yield
In pentane introduction of B2H6 (from Na(BH4) and (C2H5)2O*BF3 in diglyme) in the pentane-soln.; evapn. of solvent and excess of substituted pyridine;; recrystn.;;	93.9%
In pentane introduction of B2H6 (from Na(BH4) and (C2H5)2O*BF3 in diglyme) in the pentane-soln.; evapn. of solvent and excess of substituted pyridine;; recrystn.;;	93.9%
In neat (no solvent) addn. of diborane to amine at liquid N2 temp., keeping at -111°C, -78°C and 0°C consecutively, stirring at 0°C for 4-6 h (vacuum line); cooling to -78°C, removal of B2H6 by distn.;
In nitrobenzene determination of react.-enthalpy at 25°C;;
In nitrobenzene determination of react.-enthalpy at 25°C;;

α-picoline (109-06-8) → 2-picoline borane complex (3999-38-0)

Conditions	Yield
With sodium monobenzoxyborohydride In tetrahydrofuran at 40℃; for 5h; Inert atmosphere;	93%

μ-(CH3)2N-B2H52*2-CH3-C5H4N → 2-picoline borane complex (3999-38-0)

Conditions	Yield
In neat (no solvent) 28.5°C, 20min;;	83%
In neat (no solvent) 28.5°C, 20min;;	83%

α-picoline (109-06-8) + borane tetrahydrofuran → 2-picoline borane complex (3999-38-0)

Conditions	Yield
In tetrahydrofuran addn. of borane soln. to amine soln. at 0°C during 1 h, stirring for 1 h (N2); evapn. (vac.), drying (vac., overnight);

α-picoline (109-06-8) + 2-picoline borane complex (3999-38-0) → hydrotris(2-methylpyridine)boron(2+) diiodide (72541-44-7)

Conditions	Yield
With iodine In benzene borane mixed with I2 in benzene at room temp., temp. raised to 60°C, additional I2 and benzene added, soln. refluxed for 8 h, to soln. 2-CH3C5H4N added, mixt. refluxed for 2 h; soln. cooled, solvent and excess 2-methylpyridine removed by filtration, solid washed with benzene;	83.2%

2-picoline borane complex (3999-38-0) + 57272 → C29H33BCuF6N3

Conditions	Yield
at 25℃; for 1h; Glovebox;	80%

2-picoline borane complex (3999-38-0) + C24H13CuF10N2 → C23H17BCuF10N3

Conditions	Yield
at 25℃; for 1h; Glovebox;	62%

ethyl diazoalaninate (6111-99-5) + 2-picoline borane complex (3999-38-0) → ethyl 2-((2-methylpyridin-1-yl)boraneyl)propanoate

Conditions	Yield
With cytochrome c from Rhodothermus marinus, V75R M100D M103T mutant In acetonitrile at 20℃; for 6h; pH=7.4; Catalytic behavior; Microbiological reaction; enantioselective reaction;	42%
With D-glucose In acetonitrile at 20℃; for 24h; Catalytic behavior; Microbiological reaction; Sealed tube; enantioselective reaction;	42%

2-picoline borane complex (3999-38-0) + hydrogen cation + iodate (15454-31-6) → 2-methylpyridine conjugate acid (16969-46-3) + boric acid (11113-50-1)

Conditions	Yield
In water byproducts: I(1-);	A >99 B n/a
In water byproducts: I(1-);	A >99 B n/a

2-picoline borane complex (3999-38-0) + 2-methylpyridine borane complex → C6H9BN

2-picoline borane complex (3999-38-0) → 2-methylpyridine borane complex

Conditions	Yield
With 2-(2'-Chlorphenyl-4,5-diphenylimidazolyl-Radikal In tert-butylbenzene Kinetics; Reagent/catalyst;

2-picoline borane complex (3999-38-0) + ethanol (64-17-5) → α-picoline (109-06-8) + triethyl borate (150-46-9)

Conditions	Yield
With ReBr2(NO)(CH3CN)(PTA)2 at 50℃; for 4h; Kinetics; Reagent/catalyst; Temperature; Inert atmosphere;

2-picoline borane complex (3999-38-0) → hydrogen (1333-74-0)

Conditions	Yield
With ethanol In ethanol byproducts: B(OC2H5)3, 2-methylpyridine; ethanolysis of 2-methylpyridine-borane at 50°C;
With ethanol; ReBr2(NO)(CH3CN)(PTA)2 In ethanol Kinetics; byproducts: B(OC2H5)3, 2-methylpyridine; ethanolysis of 2-methylpyridine-borane with 1 mol.-% ReBr2(NO)(MeCN)(1,3,5-triaza-7-phosphaadamantane)2 at room temp. or at 50°C;

2-picoline borane complex (3999-38-0) + {[Cl2NN]Cu}(toluene) → C23H23BCl4CuN3

Conditions	Yield
In toluene at -35 - 25℃; for 1h; Inert atmosphere;	0.135 g
In (2)H8-toluene at -80.16 - 79.84℃; for 1h; Kinetics; Inert atmosphere;

2-picoline borane complex (3999-38-0) + N-(3-chloro-2-methylphenyl)-2-[(2S)-pyrrolidin-2-yl]-6-({[2-(trifluoromethyl)phenyl]carbonyl}amino)-1H-benzimidazole-4-carboxamide → N-(3-chloro-2-methylphenyl)-2-[(2S)-1-methylpyrrolidin-2-yl]-6-({[2-(trifluoromethyl)phenyl]carbonyl}amino)-1H-benzimidazole-4-carboxamide

Conditions	Yield
Stage #1: N-(3-chloro-2-methylphenyl)-2-[(2S)-pyrrolidin-2-yl]-6-({[2-(trifluoromethyl)phenyl]carbonyl}amino)-1H-benzimidazole-4-carboxamide With formaldehyd In methanol; water at 20℃; Stage #2: 2-picoline borane complex In methanol; water for 3h;	11 mg

2-picoline borane complex (3999-38-0) → C24H28B2N2Si

Conditions	Yield
Multi-step reaction with 2 steps 1: hexane; diethyl ether / 4 h / -70 - 20 °C / Inert atmosphere 2: diethyl ether / 40 h / -30 - 20 °C / Inert atmosphere View Scheme

2-picoline borane complex (3999-38-0) → C24H22N2Si

Conditions	Yield
Multi-step reaction with 3 steps 1: hexane; diethyl ether / 4 h / -70 - 20 °C / Inert atmosphere 2: diethyl ether / 40 h / -30 - 20 °C / Inert atmosphere 3: tert-butylamine / tetrahydrofuran / 15 h / 80 °C / Inert atmosphere; Sealed tube View Scheme

n-butyllithium (109-72-8, 29786-93-4) + 2-picoline borane complex (3999-38-0) → 2-picolyl-N-borane

Conditions	Yield
In diethyl ether; hexane at -70 - 20℃; for 4h; Inert atmosphere;

2-picoline borane complex (3999-38-0) + 4-diazo-2-tosyl-1,4-dihydroisoquinolin-3(2H)-one → C22H23BN2O3S

Conditions	Yield
With tetrakis(actonitrile)copper(I) hexafluorophosphate In 1,2-dichloro-ethane at 80℃; for 4h; Sealed tube;

Upstream product

• 109-06-8 α-picoline 
• 19287-45-7 diborane 
• 16940-66-2 sodium tetrahydroborate 
• 13292-87-0 dimethylsulfide borane complex 

Downstream Products

• 16969-46-3 2-methylpyridine conjugate acid 
• 11113-50-1 boric acid 
• 1333-74-0 hydrogen 
• 109-06-8 α-picoline 
• 150-46-9 triethyl borate 

Relevant articles and documents

A safe and scalable procedure for preparation of α-picoline-borane from sodium mono-acyloxyborohydrides and α-picoline

Sodium monobenzoxyborohydride, which is easily prepared from sodium borohydride and benzoic acid in THF in situ, is treated with α-picoline in THF under mild conditions to give α-picoline-borane in an excellent yield. This method can be a practical preparation for α-picoline-borane.

Activation of sodium borohydride via carbonyl reduction for the synthesis of amine- And phosphine-boranes

A highly versatile synthesis of amine-boranes via carbonyl reduction by sodium borohydride is described. Unlike the prior bicarbonate-mediated protocol, which proceeds via a salt metathesis reaction, the carbon dioxide-mediated synthesis proceeds via reduction to a monoformatoborohydride intermediate. This has been verified by spectroscopic analysis, and by using aldehydes and ketones as the carbonyl source for the activation of sodium borohydride. This process has been used to produce borane complexes with 1°-, 2°-, and 3°-amines, including those with borane reactive functionalities, heteroarylamines, and a series of phosphines.

Amine-boranes bearing borane-incompatible functionalities: Application to selective amine protection and surface functionalization

The first general open-flask synthesis of amine-boranes with inexpensive and readily available reagents, such as sodium borohydride, sodium bicarbonate, water, and the desired amines is described. Even amines bearing borane-reactive functionalities, such as alkene, alkyne, hydroxyl, thiol, ester, amide, nitrile, and nitro are well tolerated. Some of these novel amine-boranes represent stable molecules containing potentially incompatible electrophilic and nucleophilic centers in proximity. This convenient scalable synthesis provides a novel class of organic ligands for surface functionalization, as demonstrated by the formation of self-assembled layers of thiol- and alkoxysilane-bearing amine-boranes on gold and silica surfaces, respectively.