Volume 1

Recent advances in organic chemistry / by Alfred W. Stewart.

  • Alfred Walter Stewart
Date:
1927
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Recent advances in organic chemistry / by Alfred W. Stewart. Source: Wellcome Collection.

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    other from dimethyl-allene. In the first case, the methyl- pyrrolidine (I.) is allowed to interact with methyl iodide with the formation of dimethyl-methylpyrrolidinium iodide (II.). This substance is then decomposed with potash, whereby the ring is broken and cfes-dimethyl-methylpyrrolidine (III.) is produced. The addition of methyl iodide and decomposition of the product (IV.) with potash gives trimethylamine and the required isoprene (V.)— (I) (II.) CHS—CH—CH2 CH3—CH—C'H2 I ! CH2 ( II., ( II.. CH, \/ \/ NH CIJ.r N—I CH3 (V.) CH3—C-CH II II ch2 ch2 + N(CH3)3 + HI (IV.) CH3—CH—CH CH, CH, \ N(CH3)3 (III.) CH3—CH—C'H i II ch2 ch2 \ N(CH3), I he synthesis from dimethyl-allene is much simpler. Two molecules of hydrobromic acid are added on, forming 2-methyl-2, 4-dibromobutane, from which hydrobromic acid is again split off by means of alcoholic potash— CH3 C : C : CH, CH3 Dimethyl-allene. CBr . CH,. CH,Br / ' ‘ ch3 Methyl-dibromobutane. C . CH : CHo s CH, Isoprene. A neat isoprene synthesis has been devised 1 which starts from acetone. On treatment with sodamide, acetone yields a sodium derivative (I.), which is attacked by acetylene to form 1 Bayer and Co., D.R.P. 280226, 286920, 288271.
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