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Butatrien durch Thermolyse von Propiolsäure‐(2‐propinyl)ester
Author(s) -
Bilinski Vanda,
Dreiding André S.,
Hollenstein Hans
Publication year - 1983
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19830660743
Subject(s) - chemistry , medicinal chemistry , acetylene , methylene , thermal decomposition , organic chemistry
Flow thermolysis of 2‐propynyl propiolate (5) at 580° afforded butatriene (6) ( ca. 50%) and, as by‐products, 4‐methylene‐2‐cyclobuten‐1‐one (7) , 2‐ethynylpropenal (8) , 1‐penten‐4‐yn‐3‐one (9) , 4‐penten‐2‐ynal (10) (total ca. 10%), along with some propynal, acetylene, CO 2 and CO. In the same way, propiolic acid (1,1‐D 2 )‐2‐propynyl propiolate (11) led to (1,1‐D 2 )‐butatriene (12) and a little 4‐((D 2 )methylene)‐2‐cyclobuten‐1‐one (13). A mechanism is proposed for the transformation of 5 into 6 and of 11 into 12 , which also accounts for the formation of 7,8,9 and 10 , as well as 13. The position of one of the published 13 C‐NMR signals of butatriene (6) must be revised. Thermolysis of methyl‐ (1) and ethyl propiolate (2) resulted in small yields of 2‐buten‐4‐olide (3) and 2‐penten‐4‐olide (4).