4-methoxyphenyl 4-methylpyridine

Cyclization of the piperidone derivative (158) gave rise to diastereomer-ically pure perhydropyrido[2,l-h][l,3]oxazin-6-one (159) (94JA10819). Heating l-(3-methoxy-l-propyl)-2-hydroxy-3-cyano-4-methylpyridin-6(l//)-one in 25% sulfuric acid at 80°C for 2 h gave 8-methyl-6-oxo-2,3,4,6-tetrahydropyrido[2,1 -fo][ 1,3]oxazine-9-carboxamide (89EUP316779). 8-(4-Methoxyphenyl)-2,3,4,6-tetrahydropyrido[2, -b [1,3]oxazine-2,6-dione was obtained by cyclization of 3-[4-(4-methoxyphenyl)-2,6-dioxo-l,2,3,6-... 

Phenyl, 4-methoxyphenyl, and 4-ethoxyphenyl tellurium thiocyanates are known only in the form of their complexes with thiourea1,2 ethylenethiourea3, triphenylarsine oxide, 3-methylpyridine, 3-methylpyridine /V-oxidc, or 4-methylpyridine Af-oxide2. These compounds were prepared from the diaryl ditellurium compounds, thiocyanogen, and the ligands2. 

L = Dihexylsulfoxides trimethylamine l,eu-diaminoalkane(n = 2-4) l,2-bis-(dimethylamino)ethane. tet a lethylpiperid ne pyridine, 4-methyIpyridine 2-methylpyridinc, pyridine 1-oxide 2-, 3-. and 4-methylpyridine 1-oxides triphenylphosphane triphenylphosphane oxide, sulfide, and selenidc " tributylphosphane selenide , tris[4-methoxyphenyl]phosphane selenide, 1,2-bis(diphenylphosphano)ethane f -diselenide, thiourea, letramethylthiourea, dithioxamide dimethylacetamide ... 

Abbreviations Ac acetyl Bn benzyl BSP 1-benzenesulfinyl piperidine BTIB bis(trifluoroacetoxy)iodobenzene DAST (diethylamino)sulfur trifluoride DDQ 2,3-dichloro-5,6-dicyano-/)-benzoquinone DMDO dimethyldioxirane DMTSF dimethyl(methylthio)sulfonium tetrafluoroborate DMTST dimethyl(methylthio)sulfonium triflate DTBMP 2,6-Ai-tert-butyl-4-methylpyridine DTBP 2,6-di-tert-butylpyridine DTBPl 2,6-di-tert-butylpyridinium iodide FDCPT l-fluoro-2,6-dichloropyridinium triflate FTMPT l-fluoro-2,4,6-trimethylpyridinium triflate IDCP iodonium dicollidine perchlorate IDCT idonium dicollidine triflate LPTS 2,6-lutidinium p-toluenesulfonate LTMP lithium tetramethylpiperidide Me methyl MPBT S-(4-methoxyphenyl) benzenethiosulflnate NBS A-bromosuccinimide NIS A-iodosuccinimide NlSac A-iodosaccharin PPTS pyridinium p-toluenesulfonate TBPA tris(4-bromophenyl)ammoniumyl hexachloroantimonate Tf trifluoromethanesulfonyl TMTSB methyl-bis(methylthio)sulfonium hexachloroantimonate TMU tetramethylurea Tr trityl TTBP 2,4,6-tri-tert-butylpyrimidine. 

---