adds to the last open position of the extended eneone system. Thus, 114
is obtained.^23
HO O
OHOH112H 2 SO 4
HO O
113HO OOHOH H 2 SO 4
HO OOH114H 2 C=OPain receptors become sensitized during inflammation or from a
related stimuli, and consequently often release glutamate. That amino
acid then acts on NMDA receptors on neurons, and in the process
further sensitizes those to pain stimuli. This sequence then causes
the pain to become chronic. Specific NMDA antagonists would thus
be expected to relieve chronic pain by interrupting that chain.
Consequently, such compounds would offer a potentially nonaddictive
alternative to the opiates currently used to treat chronic pain. Reductive
amination of the acetaldehyde derivative 116 with monocarbobenzyloxy
ethylenediamine ( 116 ) leads to the now-disubstituted ethylenediamine
116. Reaction of this amine with the commercially available cyclo-
butenedione derivative 117 leads to replacement of one of the ethoxy
groups in 117 by the free amino group in 116 by what is probably
an addition–elimination sequence to afford the coupled product 118.
H 2 N NHCO 2 CH 2 C 5 H 6
115PO
C 2 H 5 O OC 2 H 5CH=O
PO
C 2 H 5 OOC 2 H 5
116
NaCNBH 3HN NHCO^2 CH^2 C^5 H^6116OOOC 2 H 5
O
OOC 2 H 5
OC 2 H 5(^117) PO
C 2 H 5 OOC 2 H 5
N NHCO^2 CH^2 C^5 H^6
Pt
118
O
O
OC 2 H 5
PO
C 2 H 5 OOC 2 H 5
N NH^2
119
N
O HN
O
PO
C 2 H 5 OOC 2 H 5
120
(CH 3 ) 3 SiBr
N
O HN
O
PO
HO OH
121
- POLYCYCLIC COMPOUNDS 39