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1.
2-Hydroxybenzoic acid heated with 2,4 - bis(4 - methoxyphenyl) - 1,3,2,4 - dithiadiphosphetane - 2,4 -disulfide, 1, gave 2 - (p - methoxyphenyl) - 4 - 1,3,2 - benzoxathiaphosphorin - 4 - one 2 - sulfide, 3, and its thio-analogue, 4, while its ethyl or phenyl esters gave 4 as the sole product. 2 - Mercaptobenzoic acid and its ethyl ester when heated with 1 produced 3 - 1,2 - benzodithiole - 3 - one, 8, 3 -1,2 - benzodithiole - 3 - thione, 9, and 2- (p - methoxyphenyl) - 4 - 1,3,2 - benzodithia - phosphorin - 4 - one 2 - sulfide, 10. The reaction of 2 -aminobenzoic acid with 1 gave 1,2 - dihydro - 2 - (p - methoxyphenyl) - 4 - 3,1,2 - benzoxaphosphorin - 4 - one 2 - sulfide, 12. Reactions of 1 with methyl 2 - aminobenzoate and 2 - aminobenzamides are described. Mechanistic considerations for the formation of the heterocyclic phosphorus compounds are presented. 相似文献
2.
Condensation of 1,3-bis(trimethylsiloxy)-1-methoxybutadiene () and 2-phenyl-2,2-dimethoxyethanal () under TiCl4 condition gave the γ-hydroxycyclopentenone product . The reaction was followed by INEPT29Si NMR. Implication to the mechanism of the reaction was discussed. 相似文献
3.
2,4,6-Triphenylpyrylium with thiosemicarbazide and thiocarbohydrazide, gives 2-pyrazolines and which undergo cyclization yielding pyrazolo(1,5-c]pyrimidine 5 and pyrazolo [2,3-d]-1,2,4-triazepine derivatives, respectively. Reaction of with phenacyl bromides gave 1,3-thiazolo[3,2-b]pyrazolo [2,3-d]-1,2,4-triazepin-4-iums . Compound on treatment with phenacyl bromides gave 1-(4'-aryl-thiazol-2'-yl)-2-pyrazoline derivatives . Compound reacts with acyl chlorides to give pyrazolo[1,5-c]pyrimidine derivatives , and with aromatic aldehydes giving the 2-(Δ2'1 pyrazolin-1-yl)-5-aryl-1,3,4-Δ2-thiadiazolines which were easily converted to the corresponding 2-(Δ2-pyrazolin-1-yl)-5-aryl-1,3,4-thiadiazoles . 相似文献
4.
Direct chlorination of 2-(2H-hexafluoropropyl)-tetra- hydrofuran gave high yield of 2-(2-chlorohexafluoropropyl)- pentachloro-2,5-dihydrofuran . Bromination of gave very complex mixture of products, from which three compounds, . 2-bromo-5-(2H-hexafluoropropyl)-furan , 3-bromo-5-(2H-hexafluoropropyl)-furan , and 2,4-dibromo-5-(2H-hexafluoropropyl)furan were isolated. Exchange fluorination of with dry KF at 240 – 300° led to a stepwise substitution of fluorines for chlorines to give mixtures of chloro-fluoro-2-(2-chlorohexafluoropropyl)-dihydrofurans ,, and , together with small amounts of 2-(2-chlorohexafluoropropyl)-3,4,5-trichlorofuran .Exchange fluorination of 3,4-dihalo-2,2,5,5-tetrafluoro- 2,5-dihydrofurans and led to a substitution of fluorine for one vinylic halogen to give 3-halo-2,2,4,5,5-pentafluoro-2,5-dihydrofurans and in good yields.Compounds – were characterised by n.m.r., m.s., and i.r. spectroscopy and elemental analysis. 相似文献
5.
A large scale synthesis for (-)-3-PPP has been developed. The racemic methoxy compound was prepared in a three step procedure in 63% yield. This was resolved as a diastereomeric salt by crystallization of the (-)-di-p-toluoyltartrate. Two crystallizations gave the pure (-)-enantiomer in 50% of the theoretical yield and with an enantiomeric excess of >95%. Demethylation using aqueous HBr gave (-)-3-PPP, (). Compound was also prepared in a stereoselective synthesis from -(-)- N-propyl-2- chloromethylpyrrolidine . By X-ray crystallography it was shown that (-)-3-PPP has the -configuration at the chiral carbon. 相似文献
6.
Condensation of 3-fluoro-2-butanone () with alkyl diethylphosphonoacetates () gave alkyl 4-fluoro-3-methyl-2-pentenoates (). Addition of bromine yielded alkyl-2,3-dibromo-4-fluoro-3-methylpentanoates () which were dehydrobrominated to alkyl 2-bromo-4-fluoro-3-methyl-2- pentenoates (). Since these compounds could not be hydrogenated to the desired alkyl 2-bromo-4-fluoro-3-methylpentanoates (), another route was taken. The esters were hydrogenated to alkyl 4-fluoro-3- methylpentanoates () which were converted to their carbanions. Treatment with bromine gave esters , and iodine gave alkyl 4-fluoro-2-iodo- 3-methylpentanoates (). Esters and were converted to alkyl 2-azido-4-fluoro-3-methylpentanoates () whose hydrogenation gave alkyl 2-amino-4-fluoro-3-methylpentanoates (). Hydrolysis afforded γ-fluoroisoleucine (). 相似文献
7.
The reaction of cesium fluoride with the 2-acyloxy 3-chloro 2-chloromethylpropanamides () gave the 3-acyloxy 3-chloromethyl azetidine 2-ones () . Treated by powdered potassium hydroxide, and were converted into the 1-oxa 4-oxo 5-aza spiro (2,3) hexanes. These reactions in heterogeneous media were very selective and gave excellent yields. 相似文献
8.
3-Methylisoxazolo[4,5-c]pyridine on reduction with BH3:THF gave, via the isolable complex , the tetrahydroisoxazolopyridine . The presence of two chlorine atoms at the 4 and 6 positions directed borane attact to the isoxazole ring, yielding the aminoethylpyridine . Both types of reduction were obtained with 6-chloroisoxazolo[4,5-c]pyridine . 相似文献
9.
Reactions of allylides () with nitrile oxides () afforded furanylglyoxylate oxime () and 6H-l,2-oxazine (). Ring transformations of and gave and pyrrolinone (), respectively. 相似文献
10.
Elena Tsankova 《Tetrahedron letters》1982,23(7):771-774
The lactone was found to be a co-product of the BF3 etherate induced cyclization of epoxyisogermacrone . The keton when treated with 100% HCOOH afforded the lactone while under the same conditions the ketol gave the corresponding ester . A mechanism is suggested for the rearrangements. 相似文献
11.
Tsutomu Kumagai Akihiko Tokida Kazuo Kidoura Osamu Seshimoto Toshio Mukai 《Tetrahedron letters》1982,23(8):873-876
The reactions of 1H-azepine derivatives ( and ) with singlet oxygen gave the [6+2] cycloadducts () and the [4+2] cycloadducts ( and ). The thermal and base-catalyzed rearrangements of the oxygen-adducts were investigated. 相似文献
12.
Conjugate addition of O-silylated ketene acetals to α,β-unsaturated carbonyl compounds in acetonitrile gave quantitative yields of the corresponding β-(alkoxycarbonyl)methyl O-silyl enolates . Site specific electrophilic substitutions of yielded the corresponding α-substituted β-(alkoxycarbonyl)-methylalkanones , , and . 相似文献
13.
A. Corsico Coda G. Desimoni M. Pappalardo P.P. Righetti P.F. Seneci G. Tacconi R. Obberti 《Tetrahedron》1985,41(12):2545-2555
The copper(II) acetate complex of isatin-3-phenylhy-drazone (2a) reacted with dimethyl acetylenedicarboxylate (DMAD) by two competitive pathways: a Cu++ oxidation of the ligand and a [2+2] cycloaddition. The former reaction gave 3-car- benindolin-2-one (13) which reacted with DMAD in a l,3-dipolar cycloaddition, to give 3a. This was synthesized by an independent route. The phenyl radical, generated in the same process, was trapped by three DMAD and gave . The [2+2] cycloaddition gave a spiro adduct 10 which, by electrocyclic ring opening and intramolecular cyclization, allowed isolation of a pyridazino [3,4-b] indole (|5a). The reaction was performed on -chlorophe-nylhydrazone 1b and the structure of 5b was demonstrated by X-ray analysis. A rationalization of the reactivity was attempted in terms of MO interactions of the reactants. 相似文献
14.
A synthesis of (2S,3S,7S)-3,7-dimethylpentadecan-2-yl acetate () and propionate () is described. (2S)-2-Methyldecan-1-yl lithium () was reacted with (3S,4S)-3,4-dimethyl-γ-butyrolactone () to yield the ketoalcohol which upon Huang-Minlon reduction furnished (2S,3S,7S)-3,7-dimethylpentadecan-2-ol (). Acylations gave the esters and . The (2S)-2-methyldecan-1-yl lithium was obtained via asymmetric synthesis. The chiral lactone was obtained from (2S,3S)-trans-2,3-epoxybutane and dimethyl malonate. 相似文献
15.
Iodine-mediated cyclization of (Z)- and (E)-{=D}-ribohept-2-enonates and gave exclusively the β-ribofuranose and α-ribofuranose derivatives and , respectively. Cyclization of the (Z)- and (E)-2-heptene-1-ol derivatives and gave ribofuranose products ( and ) and a ribopyranose (), respectively. 相似文献
16.
Irradiation of 2,4,6-tri-(tert,-butyl)thiobenzaldehyde with some alkoxy-, alkylthio-, and phenyl-allenes - gave one stereoisomer of a (2+2)-cycloadduct, viz. thietane in high yields (75–95%). Ringclosure is in agreement with MNDO-calculations. 相似文献
17.
Boźenna Golankiewicz Piotr Januszczyk Maria Gdaniec Zofia Kosturkiewicz 《Tetrahedron》1985,41(24):5989-5994
2-Acylamino-2-cyanoacetic acid ethyl esters react with 2,4-bis (4-methoxyphenyl)-1, 3, 2, 4-dithiadiphosphetane 2,4-disulfide in refluxing benzene with formation of 2-alkyl(aryl)-5-aminothiazole-4-carboxylic acid ethyl esters . Structure was established by spectroscopic means and an X ray crystallographic investigation of . X-Ray analysis revealed that the thiazole ring, exocyclic nitrogen and carbonyl group forming a hydrogen-bonded cycle are nearly coplanar. A resonance interaction is manifested by distinctly shortened /1.447 (3)/ C(carbonyl)-C(thiazole) distance. 相似文献
18.
Phosphorus pentafluoride was reported long ago to give adducts 2 PF5 ·5 NH3 (1) and nNH3·PF5 (n= 1 ? 4) (2). None of the compounds was characterised in detail. Repeating the reaction of PF5 and NH3 we found the adduct H3N·PF5, , in 8% yield besides (H2N) 2PF3 (3) and NH4PF6. However, HF and (F2P=N)3 gave in 41% yield. The 1H, 19F, and 31P n.m.r. spectra of exhibit 14NH, 14NPF(cis), and 14NP coupling. The x-ray structure determination shows almost perfect octahedral geometry at phosphorus with a PN bond length of 1.842 ā. Compound is soluble in water without decomposition. Treatment with NH3 leads to the anion H2NPF5?. Upon heating forms in good yield H2NPF4 and NH4PF6. Without a solvent and NH3 react to give (H2N) 2PF3. A mechanism for the ammonolysis of PF5 is proposed. 相似文献
19.
1,3-Di-tert-butylisobenzofuran reacts with singlet oxygen with rate constant of 2.8 x 109 M?1 sec?1 to give stable endoperoxide . Thermolysis of the endopepoxide () in the ppesence of norbornene and naphthalene gave the corrpesponding epoxide and naphthols, respectively. Addition of Pd(OAc)2 improved the yield of naphtols considepably. 相似文献
20.
Methods were developed to prepare 1 -methyl-, 3-methyl- and 4-0-methyl-ψ-isocytidine by selective methylation.35O-Tetraisopropyldisiloxanyl-ψ isocytidine (8) was trimethylsilylated and then treated with MeI and, after deprotection, 1 -methyl-ψ isocytidine (6) was obtained. The 2deoxy analog (7) was also prepared in a similar manner from the 2deoxy analog (10) of 8. Treatment of 8 with CH2N2 afforded the 3-methyl-ψ-isocytidine derivative (19) as the major product. Methylation with diazomethane also occurred mainly on N3 of the 2deoxy analog 10 to form 20. Removal of the 3 5O-protecting group from 19 and 20 afforded 3-methyl-ψ-isocytidine (14) and its 2-deoxy analog (15), respectively. 2-N-Acetyl- 35O-tetraisopropyldisiloxanyl-ψ-isocytidine (24), on the other hand, gave the 4-O-methyl derivative (25) as the major product upon CH2N2 treatment. Subsequent deprotection of 25 afforded 4-O-methyl-ψ-isocytidine (29). aiv51b1p33b 相似文献