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1.
Sulfinylation of o-nitrobenzamide and subsequent hetero Diels-Alder reaction gave a series of 2-(o-nitrobenzoyl)-1,2-thiazine-1-oxides. The 2-(o-nitrobenzoyl)-1,2-thiazine-1-oxides undergo a ring opening reaction with phenyl magnesium bromide to give allylic sulfoxides, which, after [2,3]-sigmatropic rearrangement and desulfurisation, furnish unsaturated vicinal N-(o-nitrobenzoyl)-1,2-amino alcohols. Oxidation of the alcohol and reductive ring closure gave a series of bicyclic 1,2,3,4-tetrahydro-1,4-benzodiazepin-5-ones, a subset of the ‘privileged’ 1,4-benzodiazepine structure. A 4-hydroxy-1,2,5-benzothiadiazepin-1,1-dioxide was synthesised by the same route starting from o-nitrobenzenesulfonamide. 相似文献
2.
Parallel diversity-oriented synthesis of diverse 1-(1H-imidazol-1-yl)-1,2-dihydroisoquinolines via AgOTf-catalyzed three-component reaction of 2-alkynylbenzaldehyde, amine, and imidazole is described. This reaction works efficiently under mild conditions to generate a small library of imidazole-incorporated 1,2-dihydroisoquinolines. 相似文献
3.
Liangfeng Fu 《Tetrahedron letters》2010,51(3):537-11742
An efficient synthesis of lycogarubin C (3) was completed in seven steps from the known 1-(phenylsulfonyl)indole-3-carbaldehyde in 30% overall yield, via a Diels-Alder reaction between (Z)-1,2-di(1H-indol-3-yl)ethene 9b and dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate (7), followed by a Kornfeld-Boger ring contraction to form the pyrrole ring. 相似文献
4.
Iryna O. Yaremchuk Lyubov V. Muzychka Oleg B. Smolii Olexandr V. Kucher Svitlana V. Shishkina 《Tetrahedron letters》2018,59(5):442-444
The iodolactonization product obtained from methyl 7-allylpyrrolo[2,3-d]pyrimidine-6-carboxylate was used for the synthesis of novel 1,2-dihydropyrrolo[1,2-a]pyrazin-1(2H)-one derivatives, containing carboxamide- and methylamine-groups on the pyrrole ring of the heterocycle. 相似文献
5.
A variety of benzimidazo[1,2-c]quinazolin-6-ones derivatives can be accessed in moderate to good yields under simple and metal-free reaction conditions using indoles and o-benzenediamines oxidized by iodine and TBHP. This procedure works in reasonable yields for different indoles as well as o-benzenediamines thus may provide a good synthesis of quinazolinones. A TBHP oxidized ring expansion reaction mechanism that explains the synthesis of benzimidazo[1,2-c]quinazolin-6-ones were reported. 相似文献
6.
Kazuhiro Kobayashi Atsushi Takanohashi Kenichi Hashimoto Osamu Morikawa Hisatoshi Konishi 《Tetrahedron》2006,62(13):3158-3161
The NaI/TMSCl/Et3N-mediated condensation between 2-(pyrrol-1-yl)benzaldehydes and secondary amine hydrochlorides followed by intramolecular trapping of the resulting iminium carbon by the 2-position of the pyrrole ring afforded corresponding 9-dialkylamino-9H-pyrrolo[1,2-a]indoles generally in good yields. 相似文献
7.
Ladislav Habala Alexey A. Nazarov Christian G. Hartinger Sergey A. Abramkin Wolfgang Lindner Bernhard K. Keppler 《Tetrahedron》2008,64(1):137-146
Three different pathways for the synthesis of substituted trans-(±)-1,2-cyclohexanediamines as new ligands for oxaliplatin-type compounds are presented. The different synthetic routes lead (i) by the synthesis of the compound via ortho-bromination of a substituted cyclohexanone followed by reaction with hydroxylamine and reduction by hydrogen, (ii) by addition of azide to cyclohexene mediated by manganese(III) acetate and reduction by hydrogen, or (iii) by trans-dihydroxylation of cyclohexene, and subsequent conversion into the respective mesylate or tosylate, followed by substitution by azide, and reduction in the case of 4-methyl-trans-(±)-1,2-cyclohexanediamine to a preferentially equatorially, mainly axially, or exclusively equatorially or axially oriented 4-methyl group, respectively. 相似文献
8.
V. Yu. Korotaev A. Yu. Barkov P. A. Slepukhin V. Ya. Sosnovskikh 《Russian Chemical Bulletin》2012,61(9):1750-1760
1,2-Oxazine N-oxides derived from (E)-1,1,1-trifluoro-3-nitrobut-2-ene and cyclohexanone enamines underwent spontaneous rearrangement with ring contraction to give 1-pyrroline N-oxides. Reactions of (E)-1,1,1-trifluoro(trichloro)-3-nitrobut-2-enes with N-cyclopent-enylmorpholine resulted in a series of novel CX3-containing nitroalkyl enamines and g-nitro ketones; the stereochemistry of the synthesized compounds were studied by NMR spectroscopy and X-ray diffraction. 相似文献
9.
Ho Sik Kim Yoshihisa Kurasawa Chiemi Yoshii Minako Masuyama Atsushi Takada Yoshihisa Okamoto 《Journal of heterocyclic chemistry》1990,27(4):1115-1117
The reaction of the 2-substituted 6-chloroquinoxaline 4-oxides 1a or 1b with 2-fold molar amount of methyl propiolate resulted in the 1,3-dipolar cycloaddition reaction to give 8-chloro-1,3-bismethoxycarbonyl-4-(piperidin-1-yl)pyrrolo[1,2-a]quinoxaline 4a or 8-chloro-1,3-bismethoxycarbonyl-4-(morpholin-4-yl)pyrrolo-[1,2-a]quinoxaline 4b , respectively. Compound 4a or 4b was transformed into 8-chloro-3-methoxycarbonyl-4-(piperidin-1-yl)pyrrolo[1,2-a]quinoxaline 5a or 8-chloro-3-methoxycarbonyl-4-(morpholin-4-yl)pyrrolo[1,2-a]-quinoxaline 5b , respectively. The structure of 4a,b was confirmed by the NOE measurement among the C1 -H , C 2-H and C 9-H proton signals of 5a,b . An additional reaction mechanism was proposed for the ring transformation of isoxazolo[2,3-a]quinoxalines into pyrrolo[1,2-a]quinoxalines. 相似文献
10.
The synthesis of 1,2-dihydro-1-oxopyrrolo[1,2-d]-1,2,4-triazines was achieved by rearrangement of 2-pyrrolyloxadiazoles under alkaline conditions or by cyclisation of pyrrole N-ethoxymethylidene hydrazides. The cyclisation of the N-carbethoxy hydrazone of the pyrrole-2-carboxaldehyde gave the 3,4-dihydro-4-oxopyrrolo[1,2-d]-1,2,4-triazine. Electrophilic substitution reactions of the 1- and 4-pyrrolotriazinones were made either on the lactam nitrogen with methyl sulphate, benzyl chloride and monochloroacetic acid or on the pyrrole ring with bromine and nitric acid. The structure of the derivatives was determined by 1H nmr. 相似文献
11.
Giorgio Stefancich Marino Artico Silvio Massa Salvatore Vomero 《Journal of heterocyclic chemistry》1979,16(7):1443-1447
Several routes to the synthesis of the unknown 5H-pyrrolo[1,2-b][2]benzazepine ring system have been explored. 1-(2-Cyanobenzyl)pyrrole was useful as starting material to obtain 1-(2-earboxymelhylbenzyl)pyrrole and 1-(2-chloromethylbenzyl)-2-pyrrolecarboxaldehyde. Poly-phosphoric acid catalyzed intramolecular cyclization of the former substance and treatment of the latter compound with potassium cyanide led to 11-oxo-10,11-dihydro-5H-pyrrolo[1,2-b]-[2]benzazepine and to 10-cyano-5H-pyrrolo[1,2-b][2]benzazepine, respectively. Starting from these materials the synthesis of the parent nucleus 5H-pyrrole[1,2-b][2]benzazepine and its 10,11-dihydro- and 1,2,3,10,11,11a-hexahydroderivatives has been realized. 相似文献
12.
The Parham Cyclization reaction of o-lithiobenzyl chlorides (generated by low temperature halogen-metal exchange of the corresponding o-bromobenzyl chlorides with n-butyllithium) with azodicarboxylate esters provides a new entry to the 2,3-dihydro-1H-indazole-1,2-dicarboxylate ring system in moderate to good yield. 相似文献
13.
Deepak Kumar Barange 《Tetrahedron》2007,63(8):1775-1789
We describe a practical and elegant method of constructing a thiazine ring fused with benzene under mild reaction conditions. A variety of 4-iodo-2H-benzo[e][1,2]thiazine-1,1-dioxides were prepared with high regioselectivity via a two-step process involving Pd/C-mediated C-C coupling of o-halobenzenesulfonamides with terminal alkynes, followed by iodocyclization of the resulting o-(1-alkynyl)arenesulfonamide using elemental iodine in acetonitrile. The coupling reaction was carried out using 10% Pd/C-PPh3-CuI as a catalyst system in the presence of Et3N. The process worked well for bromides and iodides, and a wide array of terminal alkynes containing alkyl and aryl substituents were employed. The iodocyclization step tolerated a variety of functional groups such as hydroxy, chloro, cyano, and methoxy, producing the six-membered heterocyclic ring selectively. The resulting 4-iodo-2H-benzo[e][1,2]thiazine-1,1-dioxides participated in Sonogashira, Heck, and Suzuki reactions producing a wide range of functionally substituted benzothiazines in good yields. 相似文献
14.
Hetero-Diels-Alder reaction of N-sulfinyl per- (or poly)fluoroaniline and N-sulfinylfluoroalkanesulfonyl amine with 1,3-dienes affords the corresponding cycloadduct 3,6-dihydro-1,2-thiazine-1-oxide which is readily converted to N-per- (or poly)fluorophenyl pyrrole and N-fluoroalkanesulfonyl pyrrole under mild reaction conditions in good yields. 相似文献
15.
A new protocol has been developed for the efficient synthesis of structurally diverse 1H-pyrazolo[1,2-b]phthalazine-1,2-dicarboxylates and 1H-pyrazolo[1,2-a]pyridazine-1,2-dicarboxylates via a four-component reaction of hydrazine hydrate, dialkyl acetylenedicarboxylates, isocyanides and various cyclic anhydrides such as succinic anhydride, maleic anhydride and phthalic anhydride in ethanol/acetone (1:1) at room temperature in good to moderate yields. 相似文献
16.
Kiminori Ohta 《Tetrahedron letters》2005,46(3):483-485
Aromatic nucleophilic substitution (SNAr) reaction of 1-phenyl-o-carborane with 4-nitrofluorobenzene in the presence of NaH or KOtBu proceeded smoothly to give 1-(4-nitrophenyl)-2-phenyl-o-carborane; similar reaction affords various 1,2-diaryl-o-carboranes, which are useful precursors for macromolecular construction and drug design. 相似文献
17.
The reaction of sarcosine and 1,3-thiazolidine-4-carboxylic acid with salicylaldehyde-derived alkynes and allenes opened the way to new chromeno[4,3-b]pyrrole and chromeno[2,3-b]pyrrole derivatives. Tetrahydro-chromeno[4,3-b]pyrroles were obtained from the reaction of these secondary amino acids with O-propargylsalicylaldehyde. Interestingly, sarcosine reacted with ethyl 4-(2-formylphenoxy)but-2-ynoate to give a monocyclic pyrrole resulting from rearrangement of the initially formed 1,3-dipolar cycloadduct. Decarboxylative condensation of ethyl 4-(2-formylphenoxy)but-2-ynoate with 1,3-thiazolidine-4-carboxylic acid afforded in a stereoselective fashion the expected chromeno-pyrrolo[1,2-c]thiazole, which structure was unambiguously established by X-ray crystallography. However, the 1H,3H-pyrrolo[1,2-c]thiazole resulting from the opening of the pyran ring was also isolated. The reaction with O-buta-2,3-dienyl salicylaldehyde afforded 3-methylene-hexahydrochromeno[4,3-b]pyrrole. O-Allenyl salicylaldehyde reacted with sarcosine and 1,3-thiazolidine-4-carboxylic acid to give a new type of chromeno-pyrroles. A mechanism proposal for the synthesis of these chromeno[2,3-b]pyrroles has been presented. 相似文献
18.
The synthesis of imidazo [1,2-c] quinazoline was effected by manganese dioxide oxidation of the 5,6-dihydroimidazo [1,2-c] quinazoline which was prepared by treatment of 2-(o-nitro-phenyl)-1-hydroxyimidazole-3-oxide with zinc powder and formic acid. The synthesis of some methyl derivatives of this ring system are also described. Structural assignments for all of the products were made from spectral data. 相似文献
19.
Yuya Inaba Yu Kakibayashi Dr. Yuki Ide Dr. Jenny Pirillo Dr. Yuh Hijikata Dr. Tomoki Yoneda Prof. Dr. Yasuhide Inokuma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(17):e202200056
The recent discovery of calix[3]pyrrole, a porphyrinogen-like tripyrrolic macrocycle, has provided an unprecedented strain-induced ring expansion reaction into calix[6]pyrrole. Here, we synthesized calix[n]furan[3-n]pyrrole (n=1∼3) macrocycles to investigate the reaction scope and mechanism of the ring expansion. Single crystal X-ray analysis and theoretical calculations revealed that macrocyclic ring strain increases as the number of inner NH sites increases. While calix[1]furan[2]pyrrole exhibited almost quantitative conversion into calix[2]furan[4]pyrrole within 5 minutes, less-strained calix[2]furan[1]pyrrole and calix[3]furan were inert. However, N-methylation of calix[2]furan[1]pyrrole induced a ring-expansion reaction that enabled the isolation of a linear reaction intermediate. The mechanism analysis revealed that the ring expansion consists of regioselective ring cleavage and subsequent cyclodimerization. This reaction was further utilized for synthesis of calix[6]-type macrocycles. 相似文献
20.
Karen Fahey 《Tetrahedron letters》2008,49(36):5235-5237
Azepino and azocino[1,2-a]benzimidazoles were obtained either by treatment of 1-nitrophenyl-2-azacycloalkanes via a one-pot catalytic hydrogenation/acetylation or by treatment of the acetamides generated in the latter reaction with performic acid. This represents the first facile synthesis of eight-membered [1,2-a] alicyclic ring-fused benzimidazoles. 3-Methoxy-azepino[1,2-a]benzimidazole was elaborated to the novel potential cytotoxin, 3-(N-aziridinyl)-7,8,9,10-tetrahydro-6H-azepino[1,2-a]benzimidazole-1,4-dione. The synthesis included clarification of the reactivity of methoxy-substituted benzimidazoles towards nitration. 相似文献