Qiuhe Long

Benzotriazole-assisted synthesis of enamines

Abstract A new, facile preparation of enamines was achieved via a two-step sequence: (i) the ready formation of an N-(α-aminoalkyl)benzotriazole derivative from equimolar amounts of benzotriazole, an aldehyde, and a secondary amine, (ii) the elimination of benzotriazole from the derivative by sodium hydride in tetrahydrofuran (THF). The method provides enamines in good overall yields based on the quantity of amine used.

The chemistry of N-substituted benzotriazoles: a novel route to dienamines

Abstract Readily prepared 1,3-bisbenzotriazolyl tertiary amines were converted into dienamines via the elimination of benzotriazole moieties with sodium hydride in tetrahydrofuran. Yields compare favourably with other methods.

2-Substituted-1,2,3,4-tetrahydroisoquinolines and chiral 3-carboxyl analogues from N-benzotriazolylmethyl-N-phenethylamines

Abstract N- Benzotriazolylmethyl- N -phenethylamines 5a – 5c and 11a – 11c cyclize in the presence of aluminum chloride to produce 1,2,3,4-tetrahydroisoquinolines 6a – 6c and 12a – 12c (70–89%) via electrophilic attack of a transient iminium cation X on the tethered phenyl ring. The Bt group in 2 - benzotriazolylmethyl-1,2,3,4-tetrahydroisoquinolines 6a – 6b was replaced (i) with hydrogen by sodium borohydride to afford N -methyl-1,2,3,4-tetrahydroisoquinolines 7a – 7b or (ii) by nucleophiles, such as Grignard reagents, a silyl enol ether or triethyl phosphite, to furnish novel N -substituted-1,2,3,4-tetrahydroisoquinolines 13a – 13c , 14 or 15 , respectively. Optically active 3-substituted-1,2,3,4-tetrahydroisoquinolines 12a – 12c were similarly prepared in high yields without racemization.

EFFICIENT AND FACILE ROUTES TO NITRONES

(2000). EFFICIENT AND FACILE ROUTES TO NITRONES. Organic Preparations and Procedures International: Vol. 32, No. 2, pp. 175-183.

THE REACTIONS OF SOME ALKOXYCARBONYL ISOTHIOCYANATES WITH ALCOHOLS, PHENOLS AND AMINES

(1993). THE REACTIONS OF SOME ALKOXYCARBONYL ISOTHIOCYANATES WITH ALCOHOLS, PHENOLS AND AMINES. Organic Preparations and Procedures International: Vol. 25, No. 1, pp. 83-90.