The title molecule, C 20 H 20 N 2 O 2 S, exits in the Z form and the five-membered imidazole ring and the benzene ring of the 4methoxybenzylidene moiety are almost coplanar. Short intramolecular contacts [CÁ Á ÁS = 3.138 (4) A ˚and CÁ Á ÁN = 3.060 (4) A ˚] indicate the presence of weak C-HÁ Á ÁS and
Zur Synthese von (Z)- und (E)-3-(1H-Imidazol-4-yl)-2-propenamin und einigen 3-(1H-Imidazol-4-yl)propanaminen
✍ Scribed by Sellier, Christian ;Buschauer, Armin ;Elz, Sigurd ;Schunack, Walter
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 722 KB
- Volume
- 1992
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Synthesis of (Z)‐ and (E)‐3‐(1__H__‐imidazol‐4‐yl)‐2‐propenamine and Some 3‐(1__H__‐imidazol‐4‐yl)propanamines
3‐(1__H__‐Imidazol‐4‐yl)propanamine (6, homohistamine), an essential intermediate for the synthesis of potent impromidine‐type histamine H~2~ receptor agonists, is efficiently prepared from trans‐urocanic acid (1) by reduction of the methyl ester 2 and conversion to the saturated amide 4. Dehydration with thionyl chloride yields the nitrile 5 which is subsequently reduced to 6. Side‐chain methylated 3‐(1__H__‐imidazol‐4‐yl)propanamines 12 are available from 1__H__‐imidazole‐4‐carbaldehyde (7) and 1‐(1__H__‐imidazol‐4‐yl)ethanone (8), respectively, via unsaturated nitriles 10 and stepwise reduction. Cyclization of the appropriate 4‐bromo‐5‐oxohexanenitriles 14α with formamidine in liquid ammonia and reduction of the obtained nitriles 15 furnishes ring‐methylated amines 16. (E)‐3‐(1__H__‐Imidazol‐4‐yl)‐2‐propenamine [(E)‐23] is obtained in six steps from the trans‐ester 2 while (Z)‐23 is accessible by treating 7 with triphenyl(2‐phthalimidoethyl)phosphonium bromide (17) and final deprotection. These primary amines are valuable intermediates for the synthesis of impromidine analogues.
📜 SIMILAR VOLUMES
In the title compound, C 13 H 12 N 4 O, the C 2 N 2 O and C 3 N 2 heterocyclic rings are almost coplanar, with a dihedral angle of 9.17 (10) . The dihedral angle between the C 3 N 2 ring and the pendant phenyl ring is 88.69 (9) . In the crystal structure, weak C-HÁ Á ÁN hydrogen bonds link the molec