Cyclopropyl cyanides

Finally a general approach to synthesize A -pyrrolines must be mentioned. This is tl acid-catalyzed (NH4CI or catalytic amounts of HBr) and thermally (150°C) induced tea rangement of cyclopropyl imines. These educts may be obtained from commercial cyan> acetate, cyclopropyl cyanide, or benzyl cyanide derivatives by the routes outlined below. Tl rearrangement is reminiscent of the rearrangement of 1-silyloxy-l-vinylcyclopropancs (p. 7 83) but since it is acid-catalyzed it occurs at much lower temperatures. A -Pyrrolines constitut reactive enamines and may be used in further addition reactions such as the Robinson anei lation with methyl vinyl ketone (R.V. Stevens, 1967, 1968, 1971). 

In a 2-1. thrcc-necked round-bottomed flask surmounted by two large condensers (Notes 1 and 2) are placed 1.30 g. (3.75 moles) of powdered sodium hydroxide (Note 3) and 103.5 g. (1 mole) of 7-chlorobutyronitrilc.1 The contents of the flask are well mixed by shaking, after which the mixture is heated on a steam bath a rather vigorous reaction sets in (Note 4). The water formed in the reaction hydrolyzes some of the cyclopropyl cyanide, so that after 1 hour s heating very little liquid is apparent. The hydrolysis of the cyanide is completed by the addition of water in small portions over a period of about 2 hours and subsequent heating 15-20 ml. of water is added at first, and portions of 60-75 ml. later at intervals of 10-15 minutes until 500 ml. in all has been added. The mixture is then heated for an additional 1.5 hours with occasional stirring at the end of this time the oily layer will have disappeared. 

Cyclopropanecarboxylic acid has been prepared by the hydrolysis of cyclopropyl cyanide,3 although it is unnecessary to... 

Very little cyclopropyl cyanide is obtained unless the ether is added before complete evaporation of the ammonia. 

Cyclopropyl cyanide has been prepared by therepeated distillation of 7-chlorobutyronitrile over powdered potassium hydroxide,1- 2 3 4 5 or over a mixture of sodium hydroxide and alumina. ... 

The preparation, on a small scale, of cyclopropyl cyanide from y-chlorobutyronitrile by action of sodium in liquid ammonia, or of sodium suspended in ether, has been described.7 The present directions are based upon those given by Schlatter.8... 

Cyclopentanepropanoic acid, c405 Cyclopentene oxide, e42 Cyclopentyl bromide, b313 Cyclopentyl chloride, c93 Cyclopropyl bromide, b314 Cyclopropyl cyanide, c407... 

Bruylante , following in the steps of Henry and Dali,prepared a number of compounds by the action of the Orlgnard reagent on cyclopropyl cyanide Michlels4 worked along similar lines and like the other investigators prepared a series of alcohols. 

Cyclopentyl bromide, b263 Cyclopentyl chloride, c79 Cyclopropyl bromide, b264 Cyclopropyl cyanide, c365... 

Methyl cyclopropyl ketone has been prepared from ethyl aceto-acetate and ethylene bromide,6 and by the action of methyl-magnesium bromide on cyclopropyl cyanide.6-7 The procedure described for its preparation from 5-chloro-2-pentanone is similar to that of Zelinsky and Dengin.8 5-Chloro-2-pentanone has been prepared by a number of methods.9 The procedure given is essentially that of Boon 10 and of Forman.11 A similar procedure has been used for the preparation of the corresponding bromo-and iodoketones.10... 

This yield is based upon the 7-chlorobutyronitrile taken. When the recovered 7-chlorobutyronitrile (52-62 g.) is taken into account, the yield of cyclopropyl cyanide is about 60 per cent of the theoretical amount. 

Alicyclic nitriles are prepared by the intramolecular alkylation of halo nitriles. For example, cyclopropyl cyanide is obtained in 75-90% yield by the action of sodium amide on y-chlorobutyronitrile in ether or liquid... 

No cyclopropane-like product ions, i.e. cyclopropyl cyanide ion (7), were generated from various pyridine precursors. By using collisional activation it was shown that 4-hydroxy-or 4-aminopyridines (129) dissociate via loss of CO or HCN, respectively, to form 3H-pyrrole (130), whereas CO loss from ionized 2-hydroxy pyridine (131) gives rise to the formation of IH-pyrrole (10). In other cases, mixtures of 2H- and either IH- or 3H-pyrroles are generated, depending on the nature of the precursor (Scheme 20). 

Quite unexpected was the recently reported ring-closure reaction associated with Cl loss from the molecular ion of a-methyl-) -chloropropionitrile (132), which yields 30% C4H6N ions which have the structure of N-protonated cyclopropyl cyanide (134). The intermediacy of 133 was suggested (Scheme 21). 

The He (I) photoelectron spectra of cyclopropylacetylene and cyclopropyl cyanide resemble that of the corresponding bromide (Figure 14) in these cases... 

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