Benzylamine

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Benzylamine
Skeletal formula of benzylamine
Space-filling model of the benzylamine molecule
Names
Preferred IUPAC name
Phenylmethanamine
Other names
α-Aminotoluene
Benzyl amine
Phenylmethylamine
Identifiers
3D model (
JSmol
)
741984
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.002.595 Edit this at Wikidata
EC Number
  • 202-854-1
49783
KEGG
RTECS number
  • DP1488500
UNII
UN number 2735
  • InChI=1S/C7H9N/c8-6-7-4-2-1-3-5-7/h1-5H,6,8H2 checkY
    Key: WGQKYBSKWIADBV-UHFFFAOYSA-N checkY
  • InChI=1/C7H9N/c8-6-7-4-2-1-3-5-7/h1-5H,6,8H2
    Key: WGQKYBSKWIADBV-UHFFFAOYAL
  • c1ccc(cc1)CN
Properties
C7H9N
Molar mass 107.156 g·mol−1
Appearance Colorless liquid
Odor weak, ammonia-like
Density 0.981 g/mL[1]
Melting point 10 °C (50 °F; 283 K)[2]
Boiling point 185 °C (365 °F; 458 K)[2]
Miscible[2]
Solubility miscible in ethanol, diethyl ether
very soluble in acetone
soluble in benzene, chloroform
Acidity (pKa) 9.34[3]
Basicity (pKb) 4.66
-75.26·10−6 cm3/mol
1.543
Structure
1.38 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Flammable and corrosive
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H302, H312, H314
P260, P264, P270, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P363, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
2
0
Flash point 65 °C (149 °F; 338 K)[2][1]
Safety data sheet (SDS) Fischer Scientific
Related compounds
Related amines
 aniline
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Benzylamine is an

pharmaceuticals. The hydrochloride salt was used to treat motion sickness on the Mercury-Atlas 6 mission in which NASA astronaut John Glenn
became the first American to orbit the Earth.

Manufacturing

Benzylamine can be produced by several methods, the main industrial route being the reaction of benzyl chloride and ammonia. It is also produced by the reduction of benzonitrile and reductive amination of benzaldehyde, both done over Raney nickel.[4]

It was first produced accidentally by Rudolf Leuckart in the reaction of benzaldehyde with formamide in a process now known as the Leuckart reaction,[5] a general process in which reductive amination of aldehydes or ketones yields the corresponding amine.[6][7]

Biochemistry

Benzylamine occurs biologically from the action of the N-substituted formamide deformylase enzyme, which is produced by Arthrobacter pascens bacteria.[8] This hydrolase catalyses the conversion of N-benzylformamide into benzylamine with formate as a by-product.[9] Benzylamine is degraded biologically by the action of the monoamine oxidase B enzyme,[10] resulting in benzaldehyde.[11]

Uses

Benzylamine is used as a masked source of ammonia, since after N-alkylation, the benzyl group can be removed by hydrogenolysis:[12]

C6H5CH2NH2 + 2 RBr → C6H5CH2NR2 + 2 HBr
C6H5CH2NR2 + H2 → C6H5CH3 + R2NH

Typically a base is employed in the first step to absorb the HBr (or related acid for other kinds of alkylating agents).

Benzylamine reacts with

interfacial polymerisation of a diamine with a diacid chloride.[17]

vasodilator papaverine) and in other areas (such as disinfectant N-laurylisoquinolinium bromide). Isoquinoline itself is efficiently prepared using the Pomeranz–Fritsch reaction, but can also be prepared from benzylamine and glyoxal acetal by an analogous approach known as the Schlittler-Müller modification to the Pomeranz–Fritsch reaction. This modification can also be used for preparing substituted isoquinolines.[18]

Synthesis of HNIW from benzylamine

The

dienophile.[19] The imine is often generated in situ from an amine and formaldehyde. An example is the reaction of cyclopentadiene with benzylamine to form an aza-norbornene.[20]

Benzylamine is used in the industrial manufacturer of numerous pharmaceuticals, including

missiles, as it has lower observability characteristics such as less visible smoke.[26] HNIW is prepared by first condensing benzylamine with glyoxal in acetonitrile under acidic and dehydrating conditions.[27] Four of the benzyl groups are removed from hexabenzylhexaazaisowurtzitane by hydrogenolysis catalysed by palladium on carbon and the resulting secondary amine groups are acetylated in acetic anhydride.[27] The resulting dibenzyl-substituted intermediate is then reacted with nitronium tetrafluoroborate and nitrosonium tetrafluoroborate in sulfolane to produce HNIW.[27]

Salts

The hydrochloride salt of benzylamine, C6H5CH2NH3Cl or C6H5CH2NH2·HCl,[28] is prepared by reacting benzylamine with hydrochloric acid, and can be used in treating motion sickness. NASA astronaut John Glenn was issued with benzylamine hydrochloride for this purpose for the Mercury-Atlas 6 mission.[29] The cation in this salt is called benzylammonium and is a moiety found in pharmaceuticals such as the anthelmintic agent bephenium hydroxynaphthoate, used in treating ascariasis.[30]

Other derivatives of benzylamine and its salts have been shown to have

anti-emetic properties, including those with the N-(3,4,5-trimethoxybenzoyl)benzylamine moiety.[31] Commercially available motion-sickness agents including cinnarizine and meclizine
are derivatives of benzylamine.

Other benzylamines

basicity
.

Safety and environment

Benzylamine exhibits modest oral toxicity in rats with

LD50 of 1130 mg/kg. It is readily biodegraded.[4]

References

  1. ^ a b "Benzylamine". Sigma-Aldrich. Retrieved 28 December 2015.
  2. ^ a b c d Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  3. doi:10.1021/ja01577a030
    .
  4. ^
    ISBN 3527306730
    .
  5. doi:10.1021/jo01188a006
    .
  6. PMID 18915755
    .
  7. doi:10.1021/jo01145a001
    .
  8. ISBN 9783540857051
    .
  9. PMID 15358859
    .
  10. ^ "MAOB: Monoamine oxidase B – Homo sapiens". National Center for Biotechnology Information. 6 December 2015. Retrieved 29 December 2015.
  11. PMID 15279561
    .
  12. ^ Gatto, V. J.; Miller, S. R.; Gokel, G. W. (1993). "4,13-Diaza-18-Crown-6". Organic Syntheses; Collected Volumes, vol. 8, p. 152. (example of alklylation of benzylamine followed by hydrogenolysis).
  13. ISBN 9783319039794
    .
  14. doi:10.1002/cber.188401702178
    .
  15. doi:10.1002/cber.188601902348
    .
  16. ISBN 9780123865380
    .
  17. ISBN 9780471274001
    .
  18. ISBN 9783319039794
    .
  19. ISBN 9783527301591
    .
  20. doi:10.15227/orgsyn.068.0206
    .
  21. doi:10.1016/0960-894X(95)00473-7
    .
  22. PMID 8627614
    .
  23. PMID 18789868
    .
  24. ISBN 9783527607495
    .
  25. Janssen Pharmaceutica, N.V. . Full text
  26. ^ Yirka, B. (9 September 2011). "University chemists devise means to stabilize explosive CL-20". Phys.org. Retrieved 28 December 2015.
  27. ^
    S2CID 95545484
    .
  28. ^ "Benzylamine hydrochloride". Sigma-Aldrich. Retrieved 28 December 2015.
  29. ^ Swenson, L. S.; Grimwood, J. M.; Alexander, C. C. "13: Mercury Mission Accomplished (13.1 Preparing a Man to Orbit)". This New Ocean: A History of Project Mercury. nasa.gov. pp. 413–418.
  30. ISBN 9780203211519
    .
  31. Hoffmann La Roche . Full text
  32. ^ PubChem Public Chemical Database (26 December 2015). "1-Phenylethylamine". National Center for Biotechnology Information. Retrieved 29 December 2015.
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