الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Benzaldehyde and acetophenone are used to prepare (E)-chalcone
(1) by two different methods one of them in NaOH and the other in
sodium ethoxide
Ethylcyanoacetate with urea or thiourea gives 6-aminopyrimidine-
2,4(1H,3H)-dione (2a) and 6-amino-2-thioxo-2,3-dihydropyrimidin-
4(1H)-one (2b) in 75 % and 77 % respectively
Refluxing (E)-chalcone (1) with (2a) or (2b) gives 5,7-diphenyl
pyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione (3a) and 5,7-diphenyl-2-
thioxo-2,3-dihydropyrido[2,3-d]pyrimidin-4(1H)-one (3b) Scheme 3.
By condensation reaction compound (3a) with hydrazine hydrate
afforded
Compound (3a) upon treatment with phosphorous oxy chloride
give 2-chloro-5,7-diphenylpyrido[2,3-d]pyrimidin-4(3H)-one (6) which
reacted with sodium azide to form tetrazole ring, on the other hand these
ring can also prepared by different method using compound (5) dissolved
in acetic acid with sodium nitrite dissolved in HCl.
When compound (5) was reacted with ethylchloroacetate leads to
the corresponding ester compound (7), on further condensation with
hydrazine hydrate in ethanol it afforded (8) Scheme 6 and Scheme 7.
When the acetohydrazide (8) was treated with carbon disulphide in
the presence of potassium hydroxide, 6,8-diphenyl-1-[(5-thioxo-4,5-
dihydro-1,3,4-thiadiazol-2-yl)methyl]pyrido[2,3-d]tetrazolo[1,5-a]
pyrimidin-9(1H)-one (9) was obtained.
On the other hand the reaction of acetohydrazide (8) with
phenylisocyanate or phenylisothiocyanate gave the corresponding 2-[2-
(9-oxo-6,8-diphenylpyrido[2,3-d]tetrazolo[1,5-a]pyrimidin-1(9H)-yl)
acetyl]-N-phenylhydrazine-1-carboxamide (10a) and 2-[2-(9-oxo-6,8-
diphenylpyrido[2,3-d]tetrazolo[1,5-a]pyrimidin-1(9H)-yl)acetyl]-Nphenylhydrazine-
1-carbothioamide (10b)
By S-alkylation of 5,7-diphenyl-2-thioxo-2,3-dihydropyrido[2,3-d]
pyrimidin-4(1H)-one (3b) with ethylchloroacetate in different basic
medium such as potassium hydroxide in ethanol or potassium carbonate
anhydrous in DMF yielding the desired ethyl 2-[(4-oxo-5,7-diphenyl-3,4-
dihydropyrido[2,3-d]pyrimidin-2-yl)thio]acetate (12).
2-(methylthio)-5,7-diphenylpyrido[2,3-d]pyrimidin-4(3H)-one (11)
was prepared by refluxing (3b) with dimethyl sulphate, Compound (11)
used to prepared a previous compound (12) by using ethylchloroacetate
Hydrazinolysis of (12) afforded 2-[(4-oxo-5,7-diphenyl-3,4-di
hydropyrido[2,3-d]pyrimidin-2-yl)thio]aceto hydrazide (13) Scheme 11.
Treated compound (13) with carbon disulphide in the presence of
potassium hydroxide obtained 2-[2-{(4-oxo-5,7-diphenyl-3,4-dihydro
pyrido[2,3-d]pyrimidin-2-yl)thio}acetyl]hydrazine-1-carbodithioic acid
2-[2-{(4-oxo-5,7-diphenyl-3,4-dihydropyrido[2,3-d]pyrimidin-2-
yl)thio}acetyl]-N-phenylhydrazine-1-carboxamide (15a) and 2-[2-{(4-
oxo-5,7-diphenyl-3,4-dihydropyrido[2,3-d]pyrimidin-2-yl)thio}acetyl]-Nphenyl
hydrazine-1-carbothioamide (15b) were synthesized by the
reaction of hydrazide (13) with phenylisocyanate or phenylisothiocyanate
Compound 4 with g.acetic acid or triethyl orthoformate afforded 3-
methyl-6,8-diphenylpyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-
one (16) and 6,8-diphenylpyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-
5(1H)-one (17) in 75% and 80% yield respectively Scheme 14.
Scheme 14
Summary
IX
On the other hand compound (4) yielded 3-amino-6-oxo-7,9-
diphenyl-6H-pyrido[2’,3’:4,5]pyrimido[2,1-c][1,2,4]triazine-4-carbonitrile
(18a) and ethyl3-amino-6-oxo-7,9-diphenyl-6H-pyrido[2’,3’:4,5]pyrimido
[2,1-c][1,2,4] triazine-4-carboxylate (18b) when reacted with malono
nitrile or ethylcyano acetate respectively.
The cyclization of compound (18a) using elemental sulfur under
reflux condition providing thiazole ring (19) in 85% yield.
The corresponding sugar (20) was prepared by the condensation of
compound (4) with D-mannose in acetone yielded.