Wittig olefination of 3-aminoquinoline-2,4(1
H,3
H)-diones
rong>1rong> with ethyl (t
riphenylphospho
ranylidene)acetate (Ph
3P
![]()
rc="http://www.sciencedi
rect.com/scidi
rimg/entities/dbnd" alt="double bond; length as m-dash" title="double bond; length as m-dash" bo
rde
r="0">CHCO
2Et) affo
rded (
E)-3-amino-4-ethoxyca
rbonylmethylene-1,2,3,4-tet
rahyd
ro-2-quinolones (
E)-
rong>2rong> and py
rrolo[2,3-
c]quinoline-2,4(3a
H,5
H)-diones
rong>3rong>. An alte
rnative app
roach fo
r the synthesis of
rong>3rong> via 3-b
romoacetamidoquinoline-2,4(1
H,3
H)-diones
rong>7rong>, thei
r co
rresponding t
riphenylphosphonium salts
rong>8rong>, and ylides
rong>Arong> that unde
rgo int
ramolecula
r Wittig
reaction, was investigated. Unde
r the applied
reaction conditions, the phosphonium salts
rong>8rong> and ylides
rong>Arong> a
re so unstable that they pa
rtly decompose to 3-acetamidoquinoline-2,4(1
H,3
H)-diones
rong>9rong> du
ring the synthesis of
rong>3rong>.