Investigations on the question of multiple mechanisms in the cope rearrangement

The possible occurrence of the ionic Cope rearrangement, and other non-concerted mechanisms is discussed. The synthesis of 2 - (1 - ethyl - 1 - propenyl) -2- (3 - p - methoxyphenylallyl)malononitrile (1b) and its clean thermal 1,3 rearrangement to (1 - ethyl - 5 - p - methoxyphenyl - 2 - methyl - 4 - pentenylidene)malononitrile (4) are reported. This result contrasts with the rearrangement of 2 - (1,1 - dideuterioallyl) - 2 -(1 - ethyl - 1 - propenyl)malononitrile (1c) which isomerizes cleanly in a 3,3 rearrangement. Rearrangement of 2 - (1 - cyclohexenyl) - 2 - (3 - p - methoxyphenylallyl)malononitrile (11), however, leads sluggishly to [2 - (p - methoxy - α - vinylbenzyl)cyclohexylidene]malononitrile (19) (3,3 shift) and rearrangement of 2 - (1 - isopropyl - 2 - methyl - 1 - propenyl) - 2 -(3 - p - methoxyphenylallyl)malononitrile (12) leads, also slowly, to (1 - isopropyl - 5-p- methoxyphenyl - 2,2 - dimethyl - 4 - pentenylidene)malononitrile (14) (1,3 shift). Rearrangement of 1b in the presence of sodium borohydride allows interception of the proposed ionic intermediates and isolation of 2 - (1 - ethylpropylidene)malononitrile (5) and anethole (21c). Ion trapping experiments also gave positive results in the 3,3 rearrangement of 11. These results are discussed in terms of the ionic Cope rearrangement.     

Synthesis of Tri-And Tetrasaccharides Present in the Linkage Region of Heparin and Heparan Sulphate

Abstract

The methyl glycosides of the the tri-and tetrasaccharides present in the linkage region of heparin, methyl O-(β-D-galactopyranosyl)-(l→3)-O-(β-D-galactopyranosyl)-(l→4)-β-D-xylopyranoside and methyl O-(β-D-glucopyranosyluronic acid)-(l→3)-O-(β-D-galactopyranosyl)-(l→3)-O-(β-D-galactopyranosyl)-(l→4)-β-D-xylopyranoside sodium salt, were synthesized together with their phosphate containing analogues, methyl O-(β-D-galactopyranosyl)-(l→3)-O-(β-D-galactopyranosyl)-(l→4)-β-D-xylopyranoside 2-(disodium phosphate) and methyl O-(β-D-glucopyranosyluronic acid)-(l→3)-O-(β-D-galactopyrano-syl)-(l→3)-O-(β-D-galactopyranosyl)-(l→4)-β-D-xylopyranoside 2-(disodium phosphate) sodium salt, which are glycosides of the structure found in the linkage region of heparan sulphate.     

Application of N-(ω-bromoalkyl)tetrazoles for the preparation of bitopic ligands containing pyridylazole chelators or azole rings as building blocks for iron(II) spin crossover polymeric materials

1-(3-Bromopropyl)tetrazole, 2-(3-bromopropyl)tetrazole, 1-(4-bromobutyl)tetrazole, and 2-(4-bromobutyl)tetrazole were synthesized with the aim to prepare flexible bitopic ligands contaning 1- or 2-substituted tetrazole ring linked through 1,3-propylene or 1,4-butylene spacer with pyridylazole or azole unit. Twenty-six novel ligands i.e., α-(pyridylazolyl)-ω-(tetrazolyl)alkanes, α-(tetrazolyl)-ω-(1,2,3-triazolyl)alkanes, and α-(tetrazol-1-yl)-ω-(tetrazol-2-yl)alkanes were prepared by an alkylation of sodium salts of 5-(2-pyridyl)tetrazole, 3-(2-pyridyl)-1,2,4-triazole, 3-(2-pyridyl)pyrazole, 1,2,3-triazole, and 1,2,3,4-tetrazole with N-(ω-bromoalkyl)tetrazoles. An alkylation of 5-(2-pyridyl)tetrazole, 1,2,3,4-tetrazole, and 1,2,3-triazole afforded both N1- and N2-regioisomer whereas in the case of 3-(2-pyridyl)-1,2,4-triazole and 3-(2-pyridyl)pyrazole only N1 isomers were isolated. The positions of alkylation were confirmed by X-ray diffraction studies of 1-(5-(2-pyridyl)tetrazol-2-yl)-4-(tetrazol-1-yl)butane, 1-(3-(2-pyridyl)-1,2,4-triazol-1-yl)-4-(tetrazol-2-yl)butane, 1-(3-(2-pyridyl)pyrazol-1-yl)-4-(tetrazol-1-yl)butane, and 1-(tetrazol-1-yl)-4-(1,2,3-triazol-1-yl)butane. Preliminary investigations of magnetic properties of iron(II) complex with 1-(3-(2-pyridyl)-1,2,4-triazol-1-yl)-4-(tetrazol-1-yl)butane revealed that obtained product exhibit thermally induced spin transition accompanied by the thermochromic effect.     

Isolation of highly pure erlotinib hydrochloride by recrystallization after nucleophilic substitution of an impurity with piperazine

Optimized synthesis and purification of erlotinib hydrochloride (N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazoline-4-amine hydrochloride) were studied. Highly polar piperazine was used in a nucleophilic substitution reaction with the chlorinated intermediate byproduct N-(3-ethynylphenyl)-6(2-chloroethoxy)-7-(2-methoxyethoxy)quinazolin-4-amine hydrochloride. As a result, N-(3-ethynylphenyl)-6(2-chloroethoxy)-7-(2-methoxyethoxy)quinazolin-4-amine hydrochloride was completely transformed to N-(3-ethynylphenyl)-6(2-piperzinoethoxy)-7-(2-methoxyethoxy)quinazolin-4-amine hydrochloride. The polarity of N-(3-ethynylphenyl)-6(2-piperzinoethoxy)-7-(2-methoxyethoxy)quinazolin-4-amine hydrochloride was changed, and its molecule was enlarged. It was easy to remove this larger, more polar, compound by recrystallization. Highly pure erlotinib hydrochloride was obtained with low impurity content (<1 %). The purity of erlotinib hydrochloride was >99.9 %.     

Amino Alcohols as Potential Antibiotic and Antifungal Leads

Five focused compound libraries (forty-nine compounds), based on prior studies in our laboratory were synthesized and screened for antibiotic and anti-fungal activity against S. aureus, E. coli, K. pneumoniae, P. aeruginosa, A. baumannii, C. albicans and C. neoformans. Low levels of activity, at the initial screening concentration of 32 μg/mL, were noted with analogues of (Z)-2-(3,4-dichlorophenyl)-3-phenylacrylonitriles which made up the first two focused libraries produced. The most promising analogues possessing additional substituents on the terminal aromatic ring of the synthesised acrylonitriles. Modifications of the terminal aromatic moiety were explored through epoxide installation flowed by flow chemistry mediated ring opening aminolysis with discreet sets of amines to the corresponding amino alcohols. Three new focused libraries were developed from substituted anilines, cyclic amines, and phenyl linked heterocyclic amines. The aniline-based compounds were inactive against the bacterial and fungal lines screened. The introduction of a cyclic, such as piperidine, piperazine, or morpholine, showed >50% inhibition when evaluated at 32 μg/mL compound concentration against methicillin-resistant Staphylococcus aureus. Examination of the terminal aromatic substituent via oxirane aminolysis allowed for the synthesis of three new focused libraries of afforded amino alcohols. Aromatic substituted piperidine or piperazine switched library activity from antibacterial to anti-fungal activity with ((Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(4-methylpiperazin-1-yl)propoxy)phenyl)acrylonitrile), ((Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(4-(4-hydroxyphenyl)piperazin-1-yl)propoxy)-phenyl)acrylonitrile) and ((Z)-3-(4-(3-(4-cyclohexylpiperazin-1-yl)-2-hydroxypropoxy)-phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile) showing >95% inhibition of Cryptococcus neoformans var. grubii H99 growth at 32 μg/mL. While (Z)-3-(4-(3-(cyclohexylamino)-2-hydroxypropoxy)phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile, (S,Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(piperidin-1-yl)propoxy)phenyl)acrylonitrile, (R,Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(piperidin-1-yl)propoxy)phenyl)acrylonitrile, (Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(D-11-piperidin-1-yl)propoxy)phenyl)-acrylonitrile, and (Z)-3-(4-(3-(4-cyclohexylpiperazin-1-yl)-2-hydroxypropoxy)-phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile 32 μg/mL against Staphylococcus aureus.     

Thermodynamic functions of Ni(II) complexes with 5-(2-hydroxyphenyl)-pyrazole derivatives. A potentiometric study

Proton-ligand dissociation constants of five biologically important pyrazole derivatives, viz. [5-(2-hydroxyphenyl)-3-(pyridin-3-yl)-4-benzoyl]-pyrazol (HPPBP), [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-(3-pyridinoyl)]-pyrazol (HPNPPP), [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-benzoyl]-pyrazol (HPNPBP), [5-(2-hydroxyphenyl)-3-phenyl-4-(3-pyridinoyl)]-pyrazol (HPPPP), and [5-(2-hydroxyphenyl)-3-(3-nitrophenyl)-4-(2-furoyl) pyrazol (HPNPFP) and metal ligand stability constants of their Ni(II) complexes in 70% (v/v) dioxane-water and 0.1 M KNO₃ were determined at 298.15, 303.15, and 308.15 K by potentiometric method. Thermodynamic functions, such as, free energy change (ΔG ^○), enthalpy change (ΔH ^○) and entropy (ΔS ^○) change for dissociation and complex formation have been estimated form temperature dependence of proton-ligand and metal-ligand stability constants and interpreted in terms of feasibility of these processes.     

Synthesis of 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide

The reaction of methyl 2-bromo-6-(trifluoromethyl)-3-pyridinecarboxylate ( 1 ) with methanesulfonamide gave methyl 2-[(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridine-carboxylate ( 2 ). Alkylation of compound 2 with methyl iodide followed by cyclization of the resulting methyl 2-[methyl(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridinecarboxylate ( 3 ) yielded 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 4 ). The reaction of compound 4 with α,2,4-trichlorotoluene, methyl bromopropionate, methyl iodide, 3-trifluoromethylphenyl isocyanate, phenyl isocyanate and 2,4-dichloro-5-(2-propynyloxy)phenyl isothiocyanate gave, respectively, 4-[(2,4-dichlorophenyl)methoxy]-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazine 2,2-dioxide ( 5 ), methyl 2-[[1-methyl-2,2-dioxido-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4-yl]oxy]propanoate ( 6 ), 1,3,3-trimethyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 7 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-[3-(trifluoromethyl)phenyl]-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 8 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-phenyl-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 9 ) and N-[2,4-dichloro-5-(2-propynyloxy)phenyl]-4-hydroxy-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2] thiazine-3-carboxamide 2,2-dioxide ( 10 ).     

Linked porphyrin systems

Porphyrin monomers, 5-(monopyridyl)-10,15,20-(triphenyl)porphyrin ( 1 ), 5,10-(dipyridyl)-15,20-(diphenyl)-porphyrin ( 2 ), and 5,15-(dipyridyl)-10,20-{diphenyl)porphyrin ( 3 ), were linked by hydrocarbon chains to form a series of dimers, trimers and polymers. The 5-(monopyridyl)-10,15,20-(triphenyl)porphyrin monomers were linked by 2, 4, 6, 8 and 10 carbon chains through the alkylation of the pyridine nitrogens using the appropriate diiodoalkane to form positively charged linked dimers 4–8 . A trimer 12 was synthesized from two 5-(monopyridyl)-10,15,20-(triphenyl)porphyrin and one 5,10-(dipyridyl)-15,20-(diphenyl)porphyrin linked by a six carbon chain. Hydrocarbon linked (5,10-(dipyridyl)-15,20-(diphenyl)porphyrin)_n ( 13 ) and (5,15-(dipyridyl)-10,20-(diphenyl)porphyrin)_n ( 14 ) were also prepared.     

1,2,4-benzothiadiazine 1,1-dioxides 3. Reactions of 2-aminobenzenesulfonamide with chloroalkyl isocyanates

Reactions of 2-aminobenzenesulfonamide ( 1 ) with allyl, methyl, 2-chloroethyl aor 3-chloropropyl isocyanates gave 2-(methylureido)-, 2-(allylureido)-, 2-(2′-chloroethylureido)- and 2-(3′-chloropropylureido)-benzene sulfonamides 3a,b and 7a,b in excellent yields. Treatment of 3a,b at refluxing temperature of DMF afforded 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide ( 4 ) in good yield. However, when compounds 7a,b were refluxed in 2-propanol, 3-(2′-aminoethoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11a ) and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11b ) were obtained in a form of the hydrochloride salts 10a,b in 87% and 78% yields respectively. Heating 11b in ethanol gave a dimeric form of 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 12 ) in 55% yield. Treating of 7a,b or 11a,b with triethylamine at the refluxing temperature of 2-propanol afforded 3-(2′-hydroxyethylamino)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2a ) and 3-(3′-hydroxypropylamine)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2b ) via a Smiles rearrangement.     

Synthesis of Derivatives of Chlorin P6 Trimethyl Ester

The Vilsmeier reaction of nickel(II) chlorin P₆ trimethyl ester with 3-dimethyl-aminoacrolein yielded nickel(II) chlorin P₆ 20-(2-formylvinyl) trimethyl ester and nickel(II) chlorin P₆ 3-(1-hydroxyethyl)-3-devinyl-20-(2-formylvinyl) trimethyl ester. Also, the outgrowths of nickel(II) chlorin P₆ 20-(2-formyl) trimethyl ester and nickel(II) chlorin P₆ 3-(2-formylvinyl)-3-devinyl-20-(2-formyl) trimethyl ester were obtained by Vilsmeier reaction with dimethylformamide. By treating the derivatives of nickel(II) 20-(2-formyl)-chlorin and nickel(II) 3-(2-formylvinyl)-20-(2-formyl)-chlorin with trifluoracetic acid, the removal of the central nickel(II) ion was accomplished. The derivatives of 20-(2-formyl)-chlorin and 3-(2-formylvinyl)-20-(2-formyl)-chlorin demonstrated considerable bathochromic shift of the major absorption band in the red region of the optical spectrum.     

Synthesis and biological activity of <Emphasis Type="Italic">N</Emphasis>-(2-hydroxyethyl)cytisine derivatives

Derivatives of N-(2-hydroxyethyl)cytisine, N-(2-hydroxypropyl)-, N-(2-hydroxy-2-(1-adamantyl)ethyl)-, and N-(2-hydroxy-2-phenylethyl)cytisine, were synthesized by reduction of N-(2-oxopropyl)-, N-(2-oxo-2-(1-adamantyl)ethyl)-and N-(2-oxo-2-phenylethyl)cytisine with metal hydrides. The antiarrhythmic and analgesic activities of the prepared compounds were investigated. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 157–162, March–April, 2007.     

Novel preparation of N′-arylthiocarbamoyl-N,N-dialkylamidines and their synthetic utilities

Treatment of 5-(arylimino)-4-(dialkylamino)-5H-1,2,3-dithiazoles (2) with NaOH in aqueous EtOH at room temperature gave N′-arylthiocarbamoyl-N,N-dialkylamidines (3) in good to excellent yields. The reaction of 3 with sulfur monochloride, thiophosgene, thionyl chloride, sulfuryl chloride, N-phenylimidoyl dichloride, and phthaloyl chloride in CH₂Cl₂ gave 2, 5-(arylimino)-4-(dialkylamino)-Δ³-thiazoline-2-thiones (5), 5-(arylimino)-4-(dialkylamino)-5H-2-oxo-1,2,3-dithiazoles (6), 5-(arylimino)-4-(dialkylamino)-5H-2,2-dioxo-1,2,3-dithiazoles (7), 5-(arylimino)-4-(dialkylamino)-2-(phenylimino)-Δ³-thiazolines (8), and 3-(arylimino)-4-(dialkylamino)-2,5-benzothiazocine-1,6-diones (10) as major products, respectively.     

Synthesis and antimalarial effects of 5,6-dichloro-2-[(4-||4-(diethylamino)-i-methylbutyl] amino||-6-methyl-2-pyrirnidinyl)amino] benzimidazole and related benzimidazoles and lH-imidazo[4,5-b] pyridines

A group of fifty-five 2-[(4-11[(dialkylamino)alkyI]amino11-6-methyl-2-pyrimidinyl)amino]-benzimidazoles (VII) was synthesized in 3-88% yield by the condensation of the requisite 2-[(2-benzimidazolyl)amino]-4-chloro-6-methylpyrimidine (VI) with the appropriate polyamine in ethanol-hydrochloric acid or neat with excess amine containing potassium iodide. The 2-[(2-benzimidazolyl)amino]-6-methyl-4-pyrirnidinol precursors (V), obtained in 11-51% yield by cyclization of 2-(cyanoamino)-4-hydroxy-6-methylpyrimidine with a suitably substituted o-phenylenediamine, were chlorinated with phosphorus oxychloride to give the intermediate 2-[(2-benzimidazolyl)amino]-4-chloro-6-rnethylpyrimidines (VI) (27-99%). Oxidation of 5,6-dichloro-2-[(4-11[4-(diethylamino)-l-methylbutyl] amino 11-6-methyl-2-pyrimidinyl) amino ]benzimidazole ( 29 ) with m-chloroperbenzoic acid gave the distal N⁴'-oxide ( 31 ) (19%). Fusion of 2,3-uiaminopyridine with 2-(cyanoamino)-4-hydroxy-6-methylpyrimidine provided 2-[(4-hydroxy-6-tnethyl-2-pyrimidinyl)amino]-lH-imitlazo[4,5-b]pyrimidine (VIII) (30%), which upon chlori-nation with phosphorus oxychloride (63%) followed by amination with i N, N-diethylethylene-diamine afforded 2-(4-11[2-(diethylamino)ethyl] amino 11-6-methyl-2-pyrimidinyl)-lH-imidazo [4,5-b]pyridine (X) (8%). Thirty-eight of the novel 2-[(4-amino-6-methyl-2-pyrimidinyl)amino]-benzimidazoles possessed “curative” activity against Plasmodium berghei at single subcutaneous doses ranging from 20.640 mg./kg. Orally, thirty-one compounds exhibited suppressive activity against P. berghei comparable with or superior to the reference drugs 1-(p-chlorophenyl)-3-(4-11[2-(diethylarnino)ethyl]amino 11-6-methyl-2-pyrimidinyl)guanidine (I) and quinine hydrochloride, while twelve of them were 5 to 28 times as potent as I and quinine hydrochloride. Eight compounds also displayed strong suppressive activity against P. gallinaceum in chicks. 5,6-Dichloro-2-[(4-112-(diethylamino)ethyl]amino11-6-methyl-2-pyrimidinyl] benzimidazole (18) showed marked activity against a cycloguanil-resistant line of P. berghei, and the most promising member of the series, namely 5,6-dichloro-2-[(4-11[4-(diethylamino)-l-methylbutyl]amino11-6-methyl-2-pyrimidinyl)amino]benzimidazole ( 29 ) (Q = 28), was designated for preclinical toxico-logical studies and clinical trial. Structure-activity relationships are discussed.     

2-Phenyl-5-(trichloromethyl)-1,3,4-oxadiazoles,A new class of antimalarial substances

An investigation of hybrids of 2,5-dimethyl-1,3,4-oxadiazole (I) and α,α,α,α',α',α'-hexachloro-p-xylene (Hetol®) (II) as potential antimalarial agents led to the synthesis of representative 2-phenyI-5-(trichloromethyl)-1,3,4-oxadiazoles (VIa-f, VIII-X) and related trichloromethyl 1,2,4-oxadiazole, 1,3,4-oxadiazoles, and 1,3,4-thiadiazole (VII, XIII-XV). Treatment of the appropriately substituted benzoic: acid hydrazides (IVa-f) with trichloroacetic anhydride afforded the intermediate 1-benzoyl-2-(triehloroacetyl)hydrazines (Va-f) which were cyclized to the desired 5-(chlorophenyl, tolyl, or α,α,α-trifluorotolyl)-2-(trichloromethyl)-1,3,4-oxadiazoles (VIa-f) (44–66%) in situ utilizing phosphorous oxychloride. Chlorination of the 5-tolyl-2-(trichloromethyl)-1,3,4-oxadiazoles (VId-f) afforded 2-(trichloromethyl)-5-(α,α,α-trichloro-m- and p-tolyl)-1,3,4-oxadiazole (VIII and IX) and 2-(α,α,α,α',α',α'-hexachloro-3,5-xylyl)-5-(trichloromethyl)-1,3,4-oxadiazole (X) in 23–56% yield. Each of the 2-phenyl-5-(trichloromethyl)-1,3,4-oxadiazoles (VIa-f, VIII-X) was active against Plasmodium berghei in mice when administered in single 160 or 640 mg./kg. subcutaneous doses or given orally by drug-diet for 6 days at doses of 29–336 mg./kg./day. The 2-(trichloromethyl)-5-(α,α,α-trichlorotolyl)-1,3,4-oxadiazoles (VIII-X) were the most active compounds prepared and exhibited activity against P. berghei comparable with Hetol®. Structure-activity relationships are discussed.     

Sesquiterpenoids of the Sponge Dysidea fragilis of the North-Brittany Sea

The title sponge is shown to contain eight new sesquiterpenoids for which a common, unusual biogenetic origin is postulated. The compounds are shown to be: (–)-(1R*,4R*)-3-(3′-furyl)methyl-2-p-menthen-7-yl acetate ((–)- 8b ); two diols separated as the monoacetates (–)-(1S*,4R*)-3-(3′-furyl)methyl-l-hydroxy-2-p-menthen-7-yl acetate ((–)- 13a ) and the (–)-(1R*,4R*)-epimer (–)- 13b , the two C(4)-epimeric 4-ethoxy-3-(1′(7′),2′-p-menthadien-3′-yl)methyl-2-buten-4-olides ((+)- 14a and (–)- 14b ), (–)-3-(3′-furyl)methyl-7-nor-2-p-menthen-l-one ((–)- 11 ), (–)-(3Z)-1-(3′-furyl)-4,8-dimethylnona-3, 7-dien-2-yl acetate ((–)- 17 ), and (+)-3-(5′,7′-seco-2′(10′)-pinen-7′-yl)methylfuran ((+)- 15 ).     

Fluorocyclohexanes. Part XVII. Dehydrofluorinations of the cis and the trans isomers of 2H-1-(difluoromethyl)decafluorocyclohexane

2H-1-(Difluoromethyl)octafluorocyclohex-1-ene (I) and cobalt trifluoride at 165 °C afforded 2H-1-(trifluoromethyl)octafluorocyclohex-1-ene (IV) and four decafluorocyclohexane derivatives: the cis (III), and trans (V), -2H-1-(trifluoromethyl)-; the cis (VII), and trans (VI), 2H-1-(difluoromethyl) compounds. Dehydrofluorination of VII, using aqueous potassium hydroxide, gave only one alkene, 1-(difluoromethyl)nonafluorocyclohex-1-ene (VIII). In a slower reaction VI afforded two alkenes, mainly VIII, But also an isomer, 1-(difluoromethyl)nonafluorocyclohex-2-ene (IX) (ratio 2:1).     

Acetylenchemie 12. Mitt.: Weitere studien über die phasentransfer-katalysierte umsetzung des 9(10H)-acridinons mil alkinylhalogeniden

By the phase transfer catalyzed reaction of 9(10H)-acridinone with 1-bromo-2-propyne, 10-(2-propynyl)-9(10H)-acridinone is synthesized. As prototropic rearrangement products of this 10-(1,2-propadienyl)-9(10H)-acridinone and 10-(1-propynyl)-9(10H)-acridinone are obtained, Under the given conditins 1-bromo-2butyne leads to 10-(2-butynyl)-9(10H)-acridinone and 2-chloro-3-butyne leads to 10-(1-methyl-1,2-propddienyl)-9(10H)-acridinone, 10-(1-methyl-2-propynyl)-9(10H)-acridinone, 9-(1-methyl-2-propynyloxy)acridine and 10-[1-methyl-3-(3,4-dimethylphenyl-2-propynyl)]-9(10H)-acridinone. The formation of the products is experimentally confirmed and with published work compared.     

Hydroxymethylation and cyanoethylation of nitroimidazoles

A series of nitroimidazoles were subjected to hydroxymethylations under a variety of conditions. Hydroxymethylation of 1-(2-hydroxyethyl), 1-(2-acetoxyethyl), and 1-(2-chloroethyl) substituted 5-nitroimidazoles with paraformaldehyde in dimethyl sulfoxide yielded the respective 2-hydroxymethyl analogs (5–7). However, attempts to hydroxymethylate 1-(2-hydroxyethyl), 1-(2-acetoxyethyl), 1-(2-cyanoethyl) substituted 4-nitroimidazoles and 1-(2-hydroxyethyl)-2-nitroimidazole were unsuccessful. Treatment of 1-(2-acetoxyethyl)-5-nitro-2-imidazolecar-baldehyde(10) with hydroxylamine-O-sulfonic acid afforded a mixture of corresponding 2-carbonitrile (12) and 2-(N-hydroxy)carboximidamide (13). Hydrolysis of 10 with ethanolic hydrochloric acid yielded 8-ethoxy-5,6-dihydro-3-nitro-8H-imidazo[2,1-c] [1,4]oxazine (11) which, on subsequent reaction with hydroxylamine-O-sulfonic acid, afforded 1-(2-hydroxyethyl)-5-nitroimidazole-2-(N-hydroxy)carboximidamide (15). Reaction of 4(5)-nitroimidazole with chloropropionitrile produced a mixture of the isomeric 1-(2-cyanoethyl) substituted 4- and 5-nitroimidazoles. Treatment of 2,4(5)-dinitroímidazole with chloropropionitrile afforded a mixture of 4(5)-chloro-5(4)-nitroimidazole and 1-(2-cyanoethyl)-4-nitro-5-chloroimidazoIe. Reaction of nitroimidazoles with acrylonitrile in the presence of Triton B yielded the corresponding 1-(2-cyanoethyl) substituted derivatives.     

Studies on furan derivatives. V. A novel ethoxycarbonylmethylation of the 5-nitro-2-furan ring in the reaction of α-(2-furyl)-β-(5-nitro-2-furyl)ethynyl with N-ethoxycarbonylmethylpyridinium ylide

An unexpected product, 1-(4-ethoxycarbonylmethyl-5-nitro-2-furyl)-2-(2-furyl)-3-ethoxycarbonyl-indolizine was obtained by the reaction of α-(2-furyl)-β-(5-nitro-2-furyl)ethynyl with N-ethoxy-carbonylmethylpyridinium ylide in N,N-dimethylformamide, together with 1-(5-nitro-2-furyl)-2-(2-furyl)-3-ethoxycarbonylindolizine.     

Synthesis and properties of 5-(1,2-dihaloethyl)-2′-deoxyuridines and related analogues

The regiospecific reaction of 5-vinyl-3′,5′-di-O-acetyl-2′-deoxyuridine ( 2 ) with HOX (X = Cl, Br, I) yielded the corresponding 5-(1-hydroxy-2-haloethyl)-3′,5′-di-O-acetyl-2′-deoxyuridines 3a-c . Alternatively, reaction of 2 with iodine monochloride in aqueous acetonitrile also afforded 5-(1-hydroxy-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3c ). Treatment of 5-(1-hydroxy-2-chloroethyl)- ( 3a ) and 5-(1-hydroxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3b ) with DAST (Et₂NSF₃) in methylene chloride at -40° gave the respective 5-(1-fluoro-2-chloroethyl)- ( 6a , 74%) and 5-(1-fluoro-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6b , 65%). In contrast, 5-(1-fluoro-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6e ) could not be isolated due to its facile reaction with methanol, ethanol or water to yield the corresponding 5-(1-methoxy-2-iodoethyl)- ( 6c ), 5-(1-ethoxy-2-iodoethyl)- ( 6d ) and 5-(1-hydroxy-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3c ). Treatment of 5-(1-hydroxy-2-chloroethyl)- ( 3a ) and 5-(1-hydroxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3b ) with thionyl chloride yielded the respective 5-(1,2-dichloroethyl)- ( 6f , 85%) and 5-(1-chloro-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6g , 50%), whereas a similar reaction employing the 5-(1-hydroxy-2-iodoethyl)- compound 3c afforded 5-(1-methoxy-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6c ), possibly via the unstable 5-(1-chloro-2-iodoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine intermediate 6h . The 5-(1-bromo-2-chloroethyl)- ( 6i ) and 5-(1,2-dibromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6j ) could not be isolated due to their facile conversion to the corresponding 5-(1-ethoxy-2-chloroethyl)- ( 6k ) and 5-(1-ethoxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 61 ). Reaction of 5-(1-hydroxy-2-bromoethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 3b ) with methanolic ammonia, to remove the 3′,5′-di-O-acetyl groups, gave 2,3-dihydro-3-hydroxy-5-(2′-deoxy-β-D-ribofuranosyl)-furano[2,3-d]pyrimidine-6(5H)-one ( 8 ). In contrast, a similar reaction of 5-(1-fluoro-2-chloroethyl)-3′,5′-di-O-acetyl-2′-deoxyuridine ( 6a ) yielded (E)-5-(2-chlorovinyl)-2′-deoxyuridine ( 1b , 23%) and 5-(2′-deoxy-β-D-ribofuranosyl)furano[2,3-d]pyrimidin-6(5H)-one ( 9 , 13%). The mechanisms of the substitution and elimination reactions observed for these 5-(1,2-dihaloethyl)-3′,5′-di-O-acetyl-2′-deoxyuridines are described.