4- aminobutan-l-ol

In a reductive amination/deprotection/Davis-Beirut reaction process, o-nitrobenzaldehydes 147 and 4-(tritylthio)butan-l-amine 148 combined to form a pair of l,3-thiazepino-2H-indazoles 149. Subsequent S-oxidation gave the corresponding sulfones.The oxygen analog 150 was prepared by using 4-aminobutan-l-ol instead of 148 (14JOC6939). 

One Nitrogen and One Otlmr Heteroatom.— iV-Nitroso-l,3-oxazepines (285) have been prepared in a one-step reaction by treating 4-aminobutan-l-ol with aldehydes in the presence of nitrous acid,i and the benzoxazepines... 

Hydrolysis of this alkaloid, C14H21O5N3 (mp 238°), in acid solution gaye syringic acid (see Volume V, p. 315). Alkaline hydrolysis generated the same acid as well as ammonia and 4-aminobutan-l-ol. On this evidence structure LVI was proposed (143). Further credence is lent to this structure because a synthetic alternate (LVII) was not identical with leonurine (144). 

Racemic 2-aminobutan-l-ol (1) is a cheap chemical which can be easily resolved into both its enantiomers on an industrial scale. The asymmetric synthesis of chiral amines from hydrazines derived from (7 )-(—)-2-aminobutan-l-ol [(R)-(—)-l], using the general strategy disclosed in early works, is summarized here. The title hydrazine (4) is prepared as follows (eq 1). Treatment of the amino alcohol [(7 )-(—)-l] with excess ethyl formate followed by LAH reduction of the intermediate formamide gives the N-methylamine [(7 )-(—)-2]. IV-Nitrosation of the latter afforded (R)-(+)-3 which is next reduced to the hydrazine [( )-(—)-4] by means of LAH. Being unstable, the hydrazine (4) must be used immediately without purification. 

The final hydrogenolysis step leading to the required a-arylalk-anamine also yields lV-methyl-2-aminobutan-l-ol (2) which can be recovered and distilled in view of recycling via its transformation into the hydrazine (4). 

A reinvestigation of the geometry of the four optically active forms of 4-methyl-cyclophosphamide, prepared from (+)- and (->3-aminobutan-l-ol, has demonstrated the necessity for corrections to previous stereochemical assignments. ... 

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