5-phcnyl-2,3-dihydro

In contrast to its reaction with methyllithium, jV,Af-diethyl-5-phcnyl-3//-azepin-2-amine (1) with butylithium undergoes 4,5-addition to give 4-butyl-A, V-diethyl-5-phenyl-4,5-dihydro-3/7-azepin-2-amine (2)38. 

Diphenyl-4,5-dihydro-l,2-oxazol —> cis-3-Phcnyl-2-benzyl-aziridin 31% d.Th. 

Methoxy-4-methyl-3-oxo-2-phenyl-3,4-dihydro-5,8-quinoxalinequinone 6-Methoxy-1 -methyl-3-phcnyl-2(l //)-quinoxalinone... 

Ab initio and density functional theoretical studies of the 4 + 2-cycloaddition of 2-azabutadiene with formaldehyde predict a concerted reaction that agrees well with experimental evidence.184 The azadiene A-phcnyl-l -aza-2-cyanobuta-l, 3-dicnc reacts with electron-rich, electron-poor, and neutral dipolarophiles under mild thermal conditions.185 5,6-Dihydro-4//-1,2-oxazines have been shown to be useftd as synthon equivalents of 2-cyano-l-azabuta-1,3-dienes.186 The intramolecular Diels-Alder reaction of 1-aza-1,3-butadienes (106) can be activated by a 2-cyano substituent (Scheme 37).187 Stereoselectivity in the hetero-Diels-Alder reactions of heterobutadienes, nitrosoalkenes, and heterodienophiles has been extensively reviewed.188 The azadiene l-(t-butyldimcthylsilyloxy)-l-azabuta-l, 3-diene (107) reacts with halobenzo-quinones, naphthoquinones, and /V-phcnylmalcimidc to yield low to good yields of various pyridine heterocycles (108) (Scheme 38).189 The 4 + 2-cycloaddition of homophthalic anhydride with /V-(cinnarnylidcnc)tritylamine produces the 3,4-adduct whereas with /V-(ci nnamyI i dcnc)bcnzyI idi nc the 1,2-adduct is produced.190... 

Reaction of 2,3-dihydro-l,2-diazepin-4-ol 28 with acetic anhydride forms 2-acctyl-5-ructhyM-phcnyl-l, 2-diazabi-cyclo[3.2.0]heptane6-ol 29 in the presence of base and forms 2-acetyl-6-methyl-7-phenyl-2,3-diaza-8-oxabicy-clo[3.2.1]-6-octene 30 in the absence of base. In addition, bicyclic 29 can be transformed into oxadicyclic 30 by treatment with acid. A study using AMI semi-emperical calculations offers several different routes for these... 

This procedure is also efficient for the synthesis of other fused tetrazoles, such as ethyl l,5-dihydro-5-oxo-7-phcnyl-8-(phenylsulfonyl)tetrazolo[ 1,5- pyridine-6-carboxy late <2000J(P1)3686>. At the same time, the unexpected azido-tetrazolo tautomerization and reversible tetrazolo transformation of 3,6-diazido-l,2,4,5-tetrazine are remarkable compared to all other polyazido heteroaromatic high-nitrogen C-N compounds <2005JA12537>. 

CN 4,5-dihydro-/V-phcnyl-A/-(phenylmethyl)-ltf-imidazole-2-mcthanaminc monohydrochloride... 

CN ( )-( )-l,4-dihydro-2,6-dimelhyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylic acid 2-methoxyethyl 3-phcnyl-2-propenyl ester... 

CN (E)-4- 2- 3-( 1,1 -dimcthylethoxy )-3-oxo-1 -propcnyl]phcnyl]-1,4-dihydro-2,6-dimethyl-3,5-pyridincdicarboxylic acid diethyl ester... 

CN 7-chloro-l, 3-dihydro-3-hydroxy-5-phcnyl-2//-l,4-benzodia/.epin-2-one... 

Ethoxy-phenyl-thiophosphonylthiomethyl)-2-methoxy-5-oxo-4,5-dihydro- E2, 2-Methoxy-4-(ethoxy-phcnyl-thiophonylthio-methyl)-5-oxo-4,5-dihydro- E2, 455... 

Amino-2-benzylideneamino-3-methoxyacrylonitrile (91) and 2-methoxy-propene gave 3-mcthoxy-5,5-dimethyl-6-phcnyl-4,5-dihydro-2-pyrazinccar-... 

Dimethylamino-2,2-dimethyl-2//-azirine (27) and 4-isopropyl-2-trifluo-romethyl-5-oxazolinone (28) gave 5-dimethylamino-3-isopropyl-6,6-di-methyl-3,6-dihydro-2(l//)-pyrazinone (29) (MeCN, reflux, N2, 1 h 60% a rational mechanism was suggested) 944 analogues, like 3-allyl-5-dimethy-lamino-6,6-dimethyl-3-phcnyl-3,6-dihydro-2(l//)-pyrazinone (44%),958 were made similarly.944 958... 

Chloro-1 -methyl-3-(hioxo-3,4-dihydro-2(l//)-pyrazinone gave 5-chloro-l-methyl-3- A,-[A,-phcnyl((hiocarbamoyl)]carbamoylmethylthio -2( I //)-pyrazi-none (26) [PhHNC(=S)NHC(=0)CH2Cl, K2C03, EtOH, reflux, 4 h ... 

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