University of Groningen
Bereiding en eigenschappen van 1-alkylthio-1-alkynen
Boonstra, Harm Jacob
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to
cite from it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date:
1961
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Boonstra, H. J. (1961). Bereiding en eigenschappen van 1-alkylthio-1-alkynen s.n.
Copyright
Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the
author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately
and investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the
number of authors shown on this cover page is limited to 10 maximum.
Download date: 19-06-2017
SUMMARY
Chapter I
Preparation of' 1- alk ylthio? l - alkynes from aldehydes.
Thioacetalsof aldehydes can be converted by pyrolysis in the
presence of an acid catalyst int0 thioenolethers:
R' -CH2 - CH(SR)2 H+ RICH='CH-SR + HSR
7
Using this reaction l-alkylthio- l -alkynes can be prepared
from the corresponding aldehydes by the following sequence of
reactions:
H+
H+
R 1 C H 2 C H O d R ' C H & H ( S R ) 2 d I'CHSHSRBf2
HSR
P
HBrCHBr-SR
Chapter I1
(Alky1thio)ethynyl derivatives from dichloroethylens .
Cis- 1,2-bis-(alky1thio)ethenescan be prepared from cis-dichloroethylene o r vinylidene chloride and sodium alkanethiolate in
liquid ammonia (table 1):
C ,H, Cl2+ 2 N a S R m c i s RSCH= CHSR + 2 NaC1
The mechanisms o f t h e s e reactions a r e discussed.
Trans - dichloroethylene o r a mixture of czs- and trans-isom e r s can be used a s a starting material, i f it is f i r s t dehydrochlorinated by sodamide : F
2 HS
aN
3 ~ % [ ,iaCCI]
~
+is
RSCH= CHSR
t m s CHCl= CHC1 2 ~NH
The cis- 1, 2-bis- (alkylthio)ethylenes obtained in this manner
can be used for the preparation of (alky1thio)ethynyl derivatives
by allowing them to react with sodamide in liquid ammonia and
an alkylhalide o r a carbonyl compound respectively (tables 2, 3
and 4) :
f
R'X
4 H C-.-h C S R + R'SR
2 NaNH
2 R'X
R S C H = C H S R ~ N ~ C = C S+ R
NaSR] ~ R ' C ~ C +S R'SR
R
NH3
AR~C(OH)CECSR
RzC=O
+ HSR
~
The 1-alkylthio- 1-alkynes can be prepared inone step starting
from dichloroethylene without isolating the intermediate cis1,2-bis- (alky1thio)ethylene (table 5) :
-
1
2 NaSR
2 NaN% ; 2 RfX
RIC='CSR
NH3
NH3
For the (alky1thio)ethynes RSCsCH and the (alky1thio)ethynylcarbinols R2C(OH)C=CSRthis shorter method is l e s s satisfactory.
The (alky1thio)ethynes RSCzCH however can be prepared in
one step bg a somewhat modified procedure from trans-dichloroethylene o r a mixture of isomers.
CHC1=CHC1
1
2
C H C ~CHC1
=
]
NaC=CCl +HCiCSR
NH3
Chapter 111
Properties of l - alkylthio- 1 - alkynes.
Attention is drawn to the fact, that acetylenic compounds
X-CfC-Alkyl have a consistently higher boilingpoint than the
isomeric compounds X'- C :C- H(X and X ' a r e alkyl or alkylthio).
The difference amounts to approximately 20' and is correlated
with a higher heat of evaporation and a higher polarisability
of the f i r s t mentioned compounds.
In electrophilic additions to l-alkylthio-I.-alkynes the electrophilic fragment invariably attaches itself to C-atom 2 of the
triple bond, e. g. :
-+ R'CH2COSC2H5
R 'CEC-SC2H5 +R'CH=CC1SC2H5 ( R '
\<z3)2C=O;BFs
( R ' = H , CH3)
= H)
(CH3)2C=CR-COSC2H5 ( R ' = H , CH3)
In nucleophilic additions the nucleophilic fragment also attacks C-atom 2:
Ese
CH3C(OC2H5) = CH-SC
CH3-CeC-SC2H5
2 1
piperidine
CH3C(NC5Hlo)=CH-SC2H5
l-Ethylthio- l -propyne apparently shows the Same dualism a s
(ethy1thio)ethyne and (ethy1thio)ethynecarbonicesters. The explanation is saught iri a -E effect of the sulfur atom, which man i f e s t ~itself only on approach of a nucleophilic agent.
The radical - addition of ethanethiol to l - ethylthio- l -propyne
leads to 1, 2-bis- (ethy1thio)- 1-propene CH3C(SGH5)=CKSC2%
(Ethy1thio)ethyne and (isopropy1thio)ethyne easily form c r i s talline m e r cury salt s: