Allenes. Part XVI. The preparation of allenic and acetylenic bromides by the triphenylphosphite dibromide method

Abstract

Allenic and acetylenic bromides were obtained under mild conditions in good yield from the corresponding alcohols by treating equimolar mixtures of alcohols and pyridine with the triphenylphosphite dibromide reagent.

General procedure for the synthesis of mono-N-acylated 1,6-diaminohexanes

“…23,23-Dimethyl-26,27-dinorcholesta-5,24-dien-3)3-ol (5). The isomer which is produced in the coupling reaction (26.65 mg, 191-195 °C) was also rechromatographed on Alumina F20 and recrystallized from distilled MeOH (mp 192-194 °C with sublimation): IR (KBr) 1469, 1461, 1457.…”

“…1444, 1434, 1378. 1372,1360,1290, 1061,1053,1023, 1006, 963, 956. 907, 839, 800, 782, 685, 668 cm-1; NMR (CDC13) 5 5.8 (q, 1, 10Hz,c/tl.a"s= 17.2 Hz, C24CH=), 5.35 (m, 1, C6), 4.87 (d, 1, J = 11.7 Hz, C25=CH2J, 4.87 (d, 1, J = 16.25 Hz, C25=CH2 (trans)); 13C NMR (CDC13) <5C 149. Received January 19,1978 Studies in our laboratory required the ready availability of N-acrylyl-1,6-diaminohexane and N-(2-methylacrylyl)-1.6-diaminohexane in high purity.…”

“…The most widely used method for the synthesis of such compounds involves reaction of 2lithiomethylpyridines (1) with an appropriate ester. [3][4][5] The mechanism of this process, as proposed by Levine and Reynolds,5 involves initial reaction of 1 with the acylating ester to form 2, which then reacts with more 1 either by proton abstraction to form the enolate of the desired ketone or by…”

Synthesis and fungicidal activity of a series of novel aryloxylepidines

“…Substituted 4‐hydroxyquinolines are synthetically accessible and were considered a viable starting point for synthesis. Bromination of 7‐chloro‐4‐hydroxyquinoline (Fig 2, 3 ) to the 4‐bromo‐compound 4 was achieved in good yield using triphenyl phosphite/bromine,8 and this material was carbonylated in ethanol to the corresponding quinoline carboxylate 5 . Reduction with sodium borohydride in methanol solution gave the desired 4‐hydroxymethylquinoline analogue 6 .…”

Allenes. Part XIX. Synthesis of (±)-hypoglycin A and configuration of the natural isomer

“…A preliminary report by Carbon et aZ.1° outlined a synthesis of hypoglycin A from 2-bromopropene in six stages but details have not been published. The present work describes a more convenient route to hypoglycin A from l-bromobuta-2,3-diene in three stages .ll The preparations of 1 -bromobut a-2,3-diene (1) 12 and diethyl l-formylaminopenta-2,3-diene-l, 1dicarboxylate (1I)l have already been described. The other two ninhydrin-sensitive components were present in small amount only and were not identified; one of them may be the corresponding spiropentane.…”