Compounds with bridgehead nitrogen. 44—the conformational analysis of perhydropyrido[1,2-c] [1,3]thiazine

The 270 MHz NMR data on trans- and cis-(H-4a, H-7)-7-ethylperhydropyrido[1,2-c][1,3]thiazine show heavy conformational bias to the trans- and S-inside cis-fused conformations, respectively. Comparison of the ¹³C NMR spectra of these anancomeric systems with the ¹³C NMR spectrum of perhydropyrido[1,2-c][1,3]thiazine indicates a trans-?S-inside cis-conformational equilibrium for the latter compound in CDCl₃ at 25°C, containing ca 75% trans-fused conformer. The ¹³C NMR spectrum of perhydropyrido[1,2-c][1,3]-thiazine at ?75°C showed 64% trans-fused conformer and 36% S-inside cis-conformer.     

Reaction of sulfenes with heterocyclic N,N-disubstituted α-aminomethyleneketones. XII. Synthesis of [1]benzothiepino[4,5-e][1,2]oxathiin derivatives

The 1,4-cycloaddition of sulfene to N,N-disubstituted (E)-4-aminomethylene-3,4-dihydro[1]benzothiepin-5(2H)-ones I occurred only in the case of aliphatic N,N-disubstitution to give in good yield 4-dialkylamino-3,4,5,6-tetrahydro[1]benzothiepino[4,5-e][1,2]oxathiin 2,2-dioxides, which are derivatives of the new heterocyclic system [1]benzothiepino[4,5-e][1,2]oxathiin. Also the reaction of I with chlorosulfene occurred only in the case of aliphatic N,N-disubstitution to afford chiefly trans-4-dialkylamino-3-chloro-3,4,5,6-tetrahydro-[1]benzothiepino[4,5-e][1,2]oxathiin 2,2-dioxides III in satisfactory yield. Adducts III were dehydrochlorinated with DBN to 4-dialkylamino-5,6-dihydro[1]benzothiepino[4,5-e][1,2]oxathiin 2,2-dioxides in good yield.     

Synthesis and Stereostructure of Saturated Isoindolone-Fused Hetero Tri-, Tetra-, and Pentacyclic Compounds

Summary. t-2-Benzoyl-t-4-phenylcyclohexane-r-1-carboxylic acid reacts with hydrazine to give the saturated 1,7-diphenyl-trans-phthalazin-4(3H)-one. The reaction of the acid with ethylenediamine yields diastereomeric trans-imidazo[2,3-a]isoindoles, which differ in their C-1 configuration. The cyclizations of the acid with cis-2-aminocyclohexane- or 4-cyclohexenemethanol result in trans-isoindolo[2,1-a][3,1]benzoxazines, while in its reactions with the analogous di-endo- and di-exo-norbornane- and -norborneneamino alcohols, the acid gives methylene-bridged isomeric di-endo-norbornanes or a norbornene derivative; the corresponding diastereomeric di-exo derivatives have also been prepared. After isolation, the structures were established by means of ¹H and ¹³C NMR spectroscopy, with application of DIFFNOE, DEPT, HMQC, HMBC, and 2D-COSY techniques.     

Synthesis and Stereostructure of Saturated Isoindolone-Fused Hetero Tri-, Tetra-, and Pentacyclic Compounds

t-2-Benzoyl-t-4-phenylcyclohexane-r-1-carboxylic acid reacts with hydrazine to give the saturated 1,7-diphenyl-trans-phthalazin-4(3H)-one. The reaction of the acid with ethylenediamine yields diastereomeric trans-imidazo[2,3-a]isoindoles, which differ in their C-1 configuration. The cyclizations of the acid with cis-2-aminocyclohexane- or 4-cyclohexenemethanol result in trans-isoindolo[2,1-a][3,1]benzoxazines, while in its reactions with the analogous di-endo- and di-exo-norbornane- and -norborneneamino alcohols, the acid gives methylene-bridged isomeric di-endo-norbornanes or a norbornene derivative; the corresponding diastereomeric di-exo derivatives have also been prepared. After isolation, the structures were established by means of ¹H and ¹³C NMR spectroscopy, with application of DIFFNOE, DEPT, HMQC, HMBC, and 2D-COSY techniques.     

Unexpected Direction of Iodocyclization of 3-Allylthio-5-phenyl-4H-1,2,4-triazole

The reaction of 3-allylthio-5-phenyl-4H-1,2,4-triazole with iodine to give a mixture of 5,6-dihydro-5-iodomethyl-3-phenyl[1,3]thiazolo[2,3-c][1,2,4]triazole, 6,7-dihydro-6-iodo-3-phenyl-5H-[1,2,4]triazolo[3,4-b][1,3]thiazine, 5,6-dihydro-6-iodomethyl-2-phenyl[1,3]thiazolo[3,2-b][1,2,4]triazole, and 6,7-dihydro-6-iodo-2-phenyl-5H-[1,2,4]triazolo[5,1-b][1,3]thiazine has been studied. The structure of the products obtained was established using ¹H NMR spectroscopy of their dehydriodination products.     

Stereoselective synthesis of dihydrothiadiazinoazines and dihydrothiadiazinoazoles and their pyrolytic desulfurization ring contraction

Intramolecular base catalyzed C-C bond formation led to exclusive stereoselective syntheses of trans-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines, trans-7,8-dihydro-6H-[1,2,4]triazino[3,4-b][1,3,4]thiadiazin-4-ones, and trans-3,4-dihydro-2H-[1,3,4]thiadiazino[2,3-b]quinazolin-10-one. trans-6,7-Dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines isomerize slowly in CDCl₃ and more rapidly in DMSO-d₆ into the corresponding cis-stereoisomers. The other trans-6,7-dihydro-[1,3,4]thiadiazines isomerize also in DMSO-d₆ into the corresponding cis-stereoisomers. Pyrolytic conversion of these heterocyclic condensed dihydrothiadiazines into their corresponding pyrazolo[5,1-b][1,2,4]triazoles, pyrazolo[5,1-c][1,2,4]triazin-4-ones and pyrazolo[4,3-b]quinazolin-9-ones via desulfurization ring contraction is described.     

Proton magnetic resonance studies of compounds with bridgehead nitrogen atoms: XXXII—The 1H n.m.r. spectra and stereochemistry of 4-aryl-1,6,7,11b-tetrahydro-2H,4H-[1,3]oxazino[4,3-a]isoquinoline, 4-aryl-1,2,6,7,12,12b-hexahydro-4H-[1,3]oxazino[3′,4′:1,2]pyrido[3,4-b]indole and of related systems

cis(4-H,11b-H)-4-Aryl-1,6,7,11b-tetrahydro-2H,4H-[1,3]oxazino [4,3-a]isoquinoline and the related thiazino compound preferentially adopt in solution the O (or S) inside cis-conformation in contrast to cis(1-H,4a-H)-1-arylperhydropyrido[1,2-c][1,3]oxazine which adopts the trans fused conformation. 1-(β-Hydroxy-ethyl)-1,2,3,4-tetrahydro-β-carboline condenses with benzaldehyde to give the 1,3-oxazine derivative rather than the dimeric structure reported in the literature.     

Synthesis of methyl 9-(benzo[<Emphasis Type="Italic">d</Emphasis>][1,3]dioxol-5-yl)-12-aryl(heteryl,cyclohexenyl)-11-oxo-7,8,9,10,11,12-hexahydrobenzo[<Emphasis Type="Italic">b</Emphasis>][4,7]phenanthroline-10-carboxylates

By condensation of 6-aminoquinoline with methyl 2-(benzo[d][1,3]dioxol-5-yl)-4,6-dioxocyclohexanecarboxylate and aldehydes of aromatic, heteroaromatic, and cyclohexene series new 4,7-phenanthroline derivatives were synthesized. The reaction performed in 1-butanol proceeded regiospecifically and with a moderate degree of stereoselectivity resulting in a mixture of cis- and trans-methyl 9-(benzo-[d][1,3] dioxol-5-yl)-12-aryl(heteryl, cyclohexenyl)-11-oxo-7,8,9,10,11,12-hexahydrobenzo-[b][4,7]-phenanthroline-10-carboxylates (∼30: 70).     

Synthesis and proton NMR stereochemical study of 7,8,9-substituted-7,8-dihydro-4H,9H-furo[2′,3′,4′:4,4a,5]-naphth[2,1-e][1,3]oxazin-4-ones

7,8,9-Substituted-7,8-dihydro-4H,9H-furo[2′,3′,4′:4,4a,5]naphth[2,1-e][1,3]oxazin-4-ones were stereospecifically obtained as a single pair of enantiomers. Their relative trans configuration and the conformation of the dihydro oxazine ring were established by ¹H nmr 2D NOESY experiments.     

Carbyne-fluoro complexes of rhenium. Single-pot synthesis of trans-[ReF(CCH2R)-(Ph2PCH2CH2PPh2)2][BF4]

Treatment of a THF solution of trans-[ReCl(N₂)(dppe)₂] (dppe = Ph₂PCH₂CH₂PPh₂) with a 1-alkyne HCCR (R =^tBu, CO₂Me, CO₂Et, or C₆H₄Me-4), in the presence of Tl[BF₄]/[NH₄][BF₄], under sunlight, affords the corresponding carbyne-fluoro complexes trans-[ReF(CCH₂R)(dppe)₂][BF₄] in an unprecedented single-pot synthesis. Further reaction with [BU₄N]OH leads to the vinylidenefluoro compounds trans-[ReF(=C=CHR)(dppe)₂] (R = CO₂Me, CO₂Et, or C₆H₄Me-4).     

Synthesis and Reactivity of Iridium(I) Fluorido Complexes: Oxidative Addition of SF4 at trans-[Ir(F)(CO)(PEt3)2]

The facile access to the Vaska type fluorido complexes trans-[Ir(F)(CO)(PR₃)₂] [ 6 : R = Et, 7 : R = Ph, 8 : R = iPr, 9 : R = Cy, 10 : R = tBu] was achieved by halide exchange at trans-[Ir(Cl)(CO)(PR₃)₂] ( 1 – 5 ) with Me₄NF. Furthermore, the reaction of complex 6 with SF₄ gave cis,trans-[Ir(F)₂(SF₃)(CO)(PEt₃)₂] ( 11 ), whereas 8 – 10 did not react. Reactivity studies revealed that 11 can selectively be manipulated at the sulfur atom by hydrolysis or fluoride abstraction to give cis,trans-[Ir(F)₂(SOF)(CO)(PEt₃)₂] ( 12 ) and cis,trans-[Ir(F)₂(SF₂)(CO)(PEt₃)₂][AsF₆] ( 13 ), respectively.     

Low-temperature 15N NMR spectra of reduced 1,3-heterocyclic systems

The ¹⁵N NMR spectra of the O-inside cis-fused conformer of perhydropyrido[1,2-c][1,3]thiazine shows a shielding of the nitrogen of 23.0 ppm relative to the trans-fused conformer. In contrast, ¹⁵N shifts for the cis-and trans-fused conformers of perhydro-oxazolo[3,4-a]pyridine and perhydrothiazolo[3,4-a]pyridine show corresponding shieldings of only 0.6 and 2.5 ppm, respectively.     

A study of the protonation and alkylation oft-butyl isocyanide intrans-[M(CNBu-t 2(Ph2PCH2CH2PPh2)2] (M = Mo or W): Formation of carbyne-type complexes and theirtrans- tocis-isomerization

Summary Treatment of complexestrans-[M(CNBu-t)₂(dppe)₂][(1) M = Mo or W, dppe = Ph₂PCH₂CH₂PPh₂] with protic acid gives a mixture of the aminocarbyne complexestrans- pluscis-[M(CNHBu-t)(CNBu-t)(dppe)₂]⁺ (2) and the hydridocompounds [MH(CNBu-t)₂(dppe)₂]⁺ (3), whereas reaction with an alkylating agent (R⁺) appears to give the dialkylaminocarbyne compounds [M(CNRBu-t)(CNBu-t)(dppe)₂]⁺ (4) also as a mixture of thetrans andcis isomers.     

On Triazoles. XXXII. The reaction of 5-amino-1 H-1,2,4-triazolylcarbothiohydrazides with β- and γ-oxo-esters

5-Amino-lH-1,2,4-triazolylcarbothiohydrazides gave β and γ-oxo-esters in boiling ethanol [1,2,4]triazolo- [1,5-d][1,2,4,6]tetrazepine-5-thiones 3 . Analogously ethyl 2-oxocyclohexanecarboxylate provided a mixture of two diastereomeric spiro derivatives 5 and 6 . At 130°, 2-acetonyl-5-methyl-4,5-dihydro-1,3,4-oxadiazole-5-thione ( 8 ) was formed. Ring closure of 3e (R¹ = CH₃, R² = CH₂CH₂COOEt, Q = morpholino) lead to the isomeric pyrrolo[2,1-g][1,2,4]triazolo[1,5-d][1,2,4,6]tetrazepin-8(11H)-one ( 12 ) and pyrrolo[1,2-f][1,2,4]triazolo-[1,5-d][1,2,4,6]tetrazepin-10(7H)-one ( 13 ) derivatives representing two new ring systems.     

Syntheses, geometry optimization, and electronic structure of N-and C-substituted benzonaphthyridines

Synthesis of N-and C-substituted derivatives of benzo[h][1,6]naphthyridine, bearing 2-hydroxyethyl group has been made by quaternization reaction and by condensation of corresponding methylbenzonaphthyridines with formaldehyde. For six derivatives of isomeric benzo[c][1,5]-, benzo[h][1,6]-, and benzo[f][1,7]naphthyridines the ¹³C NMR spectra are discussed. For ten compounds the geometry was optimized with the AM1 and, in one case also with the ab initio 6–31G method; their effective charge values have also been calculated.     

Interaction of 7-Chloro-9-methylthio-3-phenylpyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine with Some Nucleophiles

The reactions of 7-chloro-9-methylthio-3-phenylpyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine (1) with some nucleophiles have been studied. Substitution of the chlorine atom with hydrogen occurs with ammonia in DMSO to give 9-methylthio-3-phenylpyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepin-7(8H)-one. With a methanolic solution of ammonia the 7-methoxy derivative is formed. Reaction of compound 1 with an excess of sodium methoxide in methanol gave 6,7-dimethoxy-9-methylthio-3-phenyl-5,6-dihydropyrimido[5,4-f][1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine. The corresponding 7-substituted derivatives were obtained when compound 1 was heated with morpholine or 2-(dimethylamino)ethylamine. The azomethine bond of the thiadiazepine ring is reduced by sodium borohydride to give the corresponding 5,6-dihydro derivatives.     

The synthesis of medium-sized cyclic lactams by the intramolecular friedel-crafts cyclization of isocyanates. Formation of novel pyrazolo[3,4-c]benzolactams

A series of 4-ω-phenylalkyl substituted-1H-pyrazol-5-amines has been synthesized from the corresponding α-acetylphenylalkanenitriles and methylhydrazine. They were converted into the corresponding 5-isocyanates and cyclized under Friedel-Crafts conditions to medium-sized cyclic lactams. The reaction was shown to give the 7-, 8-, 9-, and 10-membered lactams but failed to yield the 11-membered lactam. Rings synthesized were: pyrazolo[3,4-c][2]benzazepin-2(1H)-one; 10H-pyrazolo[3,4-c][2]benzazocin-10-one; pyrazolo[3,4-c][2]benzazonin-11(1H)-one; 12H-pyrazolo[3,4-c][2]benzazocin-12-one.     

Substitution reactions under NH3 chemical ionization conditions in cis-/trans-1,2-dihydroxybenzosuberans

The nucleophilic substitution reaction under NH₃ chemical ionization (CI) conditions in cis- and trans-1,2-dihydroxybenzosuberans (1–4) has been studied with the help of ND₃ CI and metastable data. The results indicate that in the parent diols 1 (cis) and 2 (trans), the substitution ion [M_sH]⁺, is produced mainly by the loss of H₂O from the [MNH₄]⁺ ion (S_Ni reaction) while in their 7-methoxy derivatives 3 and 4, the ion-molecule reaction between [M? OH]⁺ and NH₃ seems to be the major pathway for the formation of [M_sH]⁺. The substitution ion from 1 and 2 and the [MH]⁺ ion from trans-1-amino-2-hydroxybenzosuberan give similar collision-induced dissociation mass-analysed ion kinetic energy spectra. Interestingly, their diacetates do not undergo the substitution reaction.     

Specific Features of Reaction of 2-R-Benzo[e][1,3,2]dioxaphosphinin-4-ones with Perfluorodiacetyl. Synthesis and Steric Structure of 4′,5′-Bis(trifluoromethyl)-4-oxo-2-(2,2,3,3-tetrafluoropropoxy)-2λ 5-spiro[benzo[e][1,3,2]dioxaphosphinine-2,2′-[1,3,2]dioxaphosphole]

2-R-benzo[e][1,3,2]dioxaphosphinin-4-ones react with perfluorodiacetyl under mild conditions to form relatively labile spirophosphoranes containing a 1,3,2-dioxaphosphole ring. These compounds gradually convert to more stable 2-R-4,5-bis(trifluoromethyl)-1,3,2λ⁵-dioxaphosphole 2-oxides and diastereometic 2-R-4-(trifluoroacetyl)-4-(trifluoromethyl)benzo[f][1,3,2λ⁵]dioxaphosphepine 2-oxides, whose structure was confirmed by means of NMR and IR spectroscopy. The structure of 4′,5′ -bis(trifluoromethyl)-4-oxo-2-(2,2,3,3-tetrafluoropropoxy)-2λ ⁵-spiro[benzo[e][1,3,2]dioxaphosphinine-2,2′-[1,3,2]dioxaphosphole] was confirmed by X-ray diffraction analysis.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 4, 2005, pp. 587–599.Original Russian Text Copyright © 2005 by Konovalova, Mironov, Ivkova, Zagidullina, Gubaidullin, Litvinov, Kurykin.     

Synthesis and identification of new thieno[3,2-b] benzothiophenes

The reaction of 2-lithiobenzo[b]thiophenes with ketones produced 2-hydroxyalkylbenzo[b]thiophenes which were cyclized in thionyl chloride to give novel thieno[3,2-b][1]benzothiophenes. Oxidation with peroxyacetic acid gave the S,S-dioxides whose regiochemistry was identified from ¹H nmr model studies using substituted benzo[b]thiophenes and their corresponding-1,1-dioxides [1].