- Synthetic method of 2,5,6-trimethoxy-3-picolinic acid
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The invention relates to a synthetic method of 2,5,6-trimethoxy-3-picolinic acid, which mainly solves the technical problem that no effective synthetic methods are provided at present. The synthetic method provided by the invention comprises the following steps: converting 2-chloro-3-hydroxypyridine hydroxy into methoxy; carrying out methoxy nucleophilic substitution of chlorine; carrying out bromination of a pyridine ring; and carrying out methoxy selective substitution of bromine; removing bromine from n-butyllithium, reacting with carbon dioxide, and introducing carboxy so as to obtain 2,5,6-trimethoxy-3-picolinic acid. In the whole synthetic process, intermediates and object products do not need to be separated through a chromatographic column, the raw materials are cheap, and the purification is simple.
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- New 2,5-diaryl tetryhydrofurans and analogs thereof as paf antagonists
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Compounds of formula: are disclosed wherein R and R1 are (a) hydrogen;(b) haloloweralkyl;(c) halo;(d) CONR2R3 wherein R2 and R3 independently represent hydrogen, C1-8 alkyl, or C3-8 cycloalkyl;(e) loweralkenyl;(f)-COR2;(g)-CH?OR2;(h) loweralkynyl;(i)-CH?NR2R3;(j)-CH?SR2;(k) =O; or(l)-OR2;(m)-R2; Ar and Ar1 are (a) phenyl or substituted phenyl of formula where R?-R? independently represent H; R2; YO-wherein Y is loweralkenyl, loweralkynyl,-CH? ,-CH?C(O) OR2,-CH?OR2,-CH?C3-8cycloalkyl,-CH? Ar2 wherein Ar2 is phenyl or substituted phenyl,-CH?-CH(OH)-CH? OH; R2S-(O)n wherein R2 can only be C3-8 cycloalkyl and n is 0 to 2; CF?SO, CF?SO?;-CONR2R3;-NR2COR3;-OCONH?-CR2R3R? wherein R? is the same as or different from R2;-CH?OR2;-CH?CO?R2;-CH?OCOR3;-CH?O-CO-OR2;-NHCH?COOR2; halo; or N?R2R3R?X? wherein X? is an anion;(b) monoheteroaryl, di-or polyheteroaryl or fused heteroaryl containing 1 to 3 of any one or more of the heteroatoms N, S or O;(c) heteroarylalkyl;(d) heterocycloalkyl; or(e) heterocycloalkenyl. These compounds are found to have potent and specific PAF (Platelet Activating Factor) antagonistic activities.
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