Benzylidene amino pyridines

Three novel organic optical materials, 4 -(N,N-dihydroxyethylamino)-4-(pyridine-4-vinyl) stilbene, N- ((4- N, N-dihydroxyethylamino)benzylidene) -4- (pyridine-4-vinyl) aniline, and 4 -(N,N-dihydroxyethylamino)-4-(pyridine-4-vinyl)azobenzene, were synthesized [105]. Tolunitriles reacted vdth donor-substituted aromatic aldehydes in high yielding reactions of the synthesis of donor-acceptor cyanostilbenes without the need of inert atmosphere. The keys to this reaction were the use of anhydride DMF solvent and the phase transfer agent - tris(3,6-dioxaheptyl)amine (TDA). High yields of stilbenes were also obtained with amino-substituted aromatic aldehydes [106]. 

The amino group of 3-amino-6-benzylidene-6,7,8,9-tetrahydro-ll//-pyrido[2,l-b]quinazolin-ll-one was acylated with ethyl oxalyl chloride in AW-dimethylacetamide in the presence of pyridine at ambient temperature, and the amido group of compound 161 (R = H, R1 = Et) was alkylated with methyl iodide. The ester groups of compounds 161 (R = H, Me, R1 = Et) were hydrolyzed (84GEP3326511). 

Tyr and Hypro, were separated on a capillary column coated with Carbowax 1540 at 102-165°C. On a preparative scale (gram amounts) the yields ranged from 50 to 98%. The application of pivalaldehyde to the preparation of the derivatives is illustrated by Scheme 5.13 (p. 109). Benzaldehyde reputedly reacts with amino acids under moderate conditions [162]. Mere mixing of the methyl esters of amino acids with a pyridine— benzaldehyde—methanol mixture (1 1 10) is reported to be sufficient for the formation of the derivatives. N-Benzylidene methyl esters of amino acids were analysed on SP-400 at 100-280°C. Pro and Hypro did not produce condensation products, however. 

Japanese workers were the first to use the reactive properties of nitrile compounds to synthesize thiazolo[3,2-a]pyridin-3(2//)-ones (77S839). Ethyl a-cyanocinnamate (88, R = Ph, R = CO Et) reacts with ethyl mer-captoacetate in the presence of triethylamine to give 5-amino-2-benzyli-dene-6,8-bis (ethoxycarbonyl )-7-phenyl-7//-thiazolo [3,2-n]pyridin-3(2//)-one (89, R = R- = Ph, R = R = C02Et), which is also obtained from the reaction of 5-benzylidene-2-ethoxycarbonylmethyl-2-thiazolin-4-one (90a) with ehtyl a-cyanocinnamate (77S839). Reaction of 90a,b with ben-zylidenemalononitrile (88, R- = Ph, R" = CN) and of 90c with ethyl a-cyanocinnamate furnish the respective bicyclic compounds 89 [83ZN(B)781] (Scheme 21). Similar results were also obtained from 88 (R = furan-2-yl-or thiophen-2-yl) (86M105). 

Bis-f2-hydroxy-athyl]-(4-amino-phcnyl)- 532 Bis-[ 2-hydroxy-athyl]-(4-nitro-phenyl)- 532 Bis-findanyl-(2)]- 252 Bis-f2-(bzw. 4)-methyl-cyclohexyl]- 442 Bis-f2-methyl-cyclohexyl]- 542 Bis-fnaphthyl-(2)-methyl]- 2.30 Bis-[2-nitro-3-methoxy-phenylJ- 5/7 Bis-[3-pentyloxy-propylj- 126 Bis-f 4-phenoxy-butylf- 126 Bis-f7-phenoxy-heptylj- 126 Bis-f6-phenoxy-hexyl]- 126 Bis-[3-(2-phenyl-athoxy)-propyl]- 126 Bis-[5,6,7,8-tetrahydro-chinolyl-(3)-methyl]- 127 Bis-[6,7,8.9-tetrahydro-5H-(cyclohepta-[b]-pyridin)-3-ylmethyl]- 127 Bis-fl-thienyl-(2)-athyl]- 430 (2-Brom-phenyl)-(4-nitro-benzyliden)- 607 Butyl- 27, 118, 413, 418... 

Several reactions involving jS-eliminations from 2-amino-2-deoxyhexonic acid derivatives have been reported. For example, 2-benzamido-4,6-0-benzylidene-2-deoxy-D-gluconic acid (87, R = H), on heating in pyridine... 

Thio sugar synthesis by this route involves sulfur as the attacking group X, and, again, the greatest success has been achieved when Y is an amino group, as in the synthesis of methyl 3-amino-3-deoxy-2-thio-a-D-allo-pyranoside (114). Methyl 3-amino-4,0-O-benzylidene-3-deoxy-a-D-altro-pyranoside was converted to the 2-0-(methylsulfonyl)-3-iV-[(methylthio)-thiocarbonyl] derivative (110), which was cyclized in boiling pyridine. 

A soln. of methyl 4,6-0-benzylidene-3-deoxy-3-(dithiocarbomethoxy)amino-2-0-methylsulfonyl- -D-altropyranoside in pyridine refluxed 15 hrs. under Ng... 

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