Syntheses of 1,4-Diazabicyclo[4.4.0]decanes, 1,4-Diazabicyclo[4.3.0]nonanes and 1,8-Diazabicyclo[4.3.0]nonanes

Abstract

A new synthesis for 1,4-diazabicyclo [4.4.0 Jdecane has been developed. The synthesis of a series of 1,4-diazabicyclo [4.3.01nonanes has been accomplished for the first time. The 1,8-diazabicyclo [4.3.0 Jnonane system has also been synthesized for the first time. A new method for the preparation of 2-aminomethylpiperidines is also reported.

Synthesis and Structure−Activity Relationships of a New Model of Arylpiperazines. 3. 2-[ω-(4-Arylpiperazin-1-yl)alkyl]perhydropyrrolo- [1,2-c]imidazoles and -perhydroimidazo[1,5-a]pyridines: Study of the Influence of the Terminal Amide Fragment on 5-HT1A Affinity/Selectivity

“…The compounds 3a,b were synthesized by published procedures. The physical data are in agreement with those given in refs and .…”

“…The general strategy for the synthesis of compounds 2a − j is summarized in Scheme . Treatment of 4-(ω-chloroalkanoyl)-1-arylpiperazines 4 with hydantoins 3 , , in the presence of NaH and N , N -dimethylformamide (DMF), gave the corresponding intermediates 5 (in 60−70% yield), which were reduced by LiAlH 4 in THF to provide the desired compounds 2a − j (in 40−67% yield). This sequence is particularly useful for preparing compounds 2 , since the direct reduction of 1 29 (obtained in 20−50% yield) proceeds with low overall yields.…”

Imines, Cyclic

“…Not only ammonia and amines, but also hydrazine [302-01-2] (78), hydrazoic acid [7782-79-8] (79-82), alkyl azidoformates (83), and acid amides, eg, sulfonamides (84) or 2,4-dioxopyrimidines (85), have been used as ring-opening reagents for ethyleneimine with nitrogen being the nucleophilic center (1). The 2-oxopiperazine skeleton has been synthesized from α-amino acid esters and ethyleneimine (86)(87)(88)(89).…”

A study of some octahydroimidazo[1,5‐a] pyridines. A new example of ring‐chain tautomerism

“…While this work was in progress Crabb and Newton (3) challenged the synthesis of octahydroimidazo- [ 1,5u]pyridine by the method originated by Freed and Day. They repeated the work of Freed and Day, reacting Schemr I 0c02c2"5 A ethyl 2piperidinecarboxylate with isocyanic acid to obtain the octahydroimidazo [ 1,5u]pyridine-l,3-dione (IV) reported in reference (1). They claimed, however, that the product of reduction with lithium aluminum hydride was not octahydroimidazo [ 1,5u Ipyridine but 2-methylaminomethylpiperidine (V) (See Scheme 1).…”