Conversion of 1,3‐Dimethyl‐5‐(Arylazo)‐6‐Amino‐Uracils to 1,3‐Dimethyl‐5‐(Arylazo)‐Barbituric Acids: Spectroscopic Characterization,Photophysical Property and Determination of pKa of the Products

The study of inter‐conversion between molecules, especially biologically and pharmaceutically important molecules, is extremely important. This study reports the inter‐conversion between two azo‐derivtives: azo‐6‐aminouracils to azo‐barbituric acids. We successfully converted the 1,3‐dimethyl‐5‐(arylazo)‐6‐aminouracils ( Uazo‐1 to Uazo‐4 ) to 1,3‐dimethyl‐5‐(arylazo)‐barbituric acids ( BAazo‐1 to BAazo‐4 ) (where aryl?C₆H₅‐( 1 ); p‐MeC₆H₄‐( 2 ), p‐ClC₆H₄‐( 3 ), and p‐NO₂C₆H₄‐( 4 )) following an acid‐hydrolysis path. The products were characterized using spectroscopic tools like UV‐vis, IR, and NMR spectroscopy. UV‐vis spectra of the as‐prepared dyes reveal that in contrast to the azo‐6‐aminouracils they are hardly responsive towards solvatochromism. IR spectra exhibit three characteristic >C?O frequencies for as‐prepared azobarbituric acids instead of two for mother azo‐6‐aminouracils. ¹H NMR spectra which reflect the existence of solution species evidence the absence of >C?NH group (characteristic imido‐H at the 6‐position of hydrazone species of azo‐6‐aminouracils) and consequence presence of >C?O group at the same position in as‐prepared azobarbituric acids. They exhibit structural emissions in the range of 400–440 nm upon excitation at 360 nm. The determined acid dissociation constant (pKa) values of BAazos increase according to the following sequence: BAazo ‐ 2 > 1 > 3 > 4 .     

Reaction of cyclic imidates with α,β‐unsaturated esters: Synthesis of new pyrrolo[2,1‐b]‐1,3‐oxazine and pyrido[2,1‐b]‐1,3‐oxazine derivatives

The cycloaddition reaction of cyclic imidates, 2‐benzyl‐5,6‐dihydro‐4H‐1,3‐oxazines 1a , 1b , 1c , 1d , 1e , 1f , with dimethyl acetylenedicarboxylate 2 , trimethyl ethylenetricarboxylate 4 , or dimethyl 2‐(methoxymethylene)malonate 6 afforded new fused heterocyclic compounds, such as methyl (6‐oxo‐3,4‐dihydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐ylidene)acetates 3a , 3b , 3c , 3d , 3e , 3f (71–79%), dimethyl 2‐(6‐oxo‐3,4,6,7‐tetrahydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐yl)malonates 5b , 5c , 5d , 5e , 5f (43–71%), or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a , 7b , 7c , 7d , 7e , 7f (32–59%), respectively. In these reactions, 1a , 1b , 1c , 1d , 1e , 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2 , 4, and 6 to give annulation products 3 , 5 , and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem., (2011).     

Novel and Stereospecific Synthesis of (2S)‐3‐(2,4,5‐Trifluorophenyl)propane‐1,2‐diol from D‐Mannitol

A stereospecific synthesis of (2S)‐3‐(2,4,5‐trifluorophenyl)propane‐1,2‐diol from D ‐mannitol has been developed. The reaction of 2,3‐O‐isopropylidene‐D ‐glyceraldehyde with 2,4,5‐trifluorophenylmagnesium bromide gave [(4R)‐2,2‐dimethyl‐1,3‐dioxolan‐4‐yl](2,4,5‐trifluorophenyl)methanol in 65% yield as a mixture of diastereoisomers (1 : 1). The Ph₃P catalyzed reaction of the latter with C₂Cl₆ followed by reduction with Pd/C‐catalyzed hydrogenation gave (2S)‐3‐(2,4,5‐trifluorophenyl)propane‐1,2‐diol with >99% ee and 65% yield.     

New Studies on [2+3] Cycloadditions of Thermally Generated N‐Isopropyl‐ and N‐(4‐Methoxyphenyl)‐Substituted Azomethine Ylides

The thermal reaction of 1‐substituted 2,3‐diphenylaziridines 2 with thiobenzophenone ( 6a ) and 9H‐fluorene‐9‐thione ( 6b ) led to the corresponding 1,3‐thiazolidines (Scheme 2). Whereas the cis‐disubstituted aziridines and 6a yielded only trans‐2,4,5,5‐tetraphenyl‐1,3‐thiazolidines of type 7 , the analogous reaction with 6b gave a mixture of trans‐ and cis‐2,4‐diphenyl‐1,3‐thiazolidines 7 and 8 . During chromatography on SiO₂, the trans‐configured spiro[9H‐fluorene‐9,5′‐[1,3]thiazolidines] 7c and 7d isomerized to the cis‐isomers. The substituent at N(1) of the aziridine influences the reaction rate significantly, i.e., the more sterically demanding the substituent the slower the reaction. The reaction of cis‐2,3‐diphenylaziridines 2 with dimethyl azodicarboxylate ( 9 ) and dimethyl acetylenedicarboxylate ( 11 ) gave the trans‐cycloadducts 10 and 12 , respectively (Schemes 3 and 4). In the latter case, a partial dehydrogenation led to the corresponding pyrroles. Two stereoisomeric cycloadducts, 15 and 16 , with a trans‐relationship of the Ph groups were obtained from the reaction with dimethyl fumarate ( 14 ; Scheme 5); with dimethyl maleate ( 17 ), the expected cycloadduct 18 together with the 2,3‐dihydropyrrole 19 was obtained (Scheme 6). The structures of the cycloadducts 7b, 8a, 15b , and 16b were established by X‐ray crystallography.     

Diastereoselective Synthesis of (Z)‐6‐(2‐Oxo‐1,2‐dihydro‐3H‐indol‐3‐ylidene)‐3,3a,9,9a‐tetrahydroimidazo[4,5‐e]thiazolo[3,2‐b]‐1,2,4‐triazin‐2,7(1H,6H)‐diones

Two efficient and diastereoselective procedures for the synthesis of (Z)‐6‐(2‐oxo‐1,2‐dihydro‐3H‐indol‐3‐ylidene)‐3,3a,9,9a‐tetrahydroimidazo[4,5‐e]thiazolo[3,2‐b]‐1,2,4‐triazin‐2,7(1H,6H)‐diones by aldol‐crotonic condensation of 1,3‐dimethyl‐3a,9a‐diphenyl‐3,3a,9,9a‐tetrahydroimidazo[4,5‐e]thiazolo[3,2‐b]‐1,2,4‐triazin‐2,7(1H,6H)‐dione with isatins under acidic or basic catalysis are reported. Isomerization in (Z)‐7‐(1‐allyl‐2‐oxo‐1,2‐dihydro‐3H‐indol‐3‐ylidene)‐1,3‐dimethyl‐3a,9a‐diphenyl‐1,3a,4,9a‐tetrahydroimidazo[4,5‐e]thiazolo[2,3‐c]‐1,2,4‐triazin‐2,8(3H,7H)‐dione was observed under basic conditions.     

Stereochemical Course of the Reaction between Thiocarbonyl Compounds and Oxiranes: Reaction with cis‐ and trans‐2,3‐Dimethyloxirane

The reactions of thiocarbonyl compounds with cis‐2,3‐dimethyloxirane ( 1a ) in CH₂Cl₂ in the presence of BF₃⋅Et₂O or SnCl₄ led to trans‐4,5‐dimethyl‐1,3‐oxathiolanes, whereas with trans‐2,3‐dimethyloxirane ( 1b ) cis‐4,5‐dimethyl‐1,3‐oxathiolanes were formed. With the stronger Lewis acid SnCl₄, the formation of side‐products was also observed. In the case of 1,3‐thiazole‐5(4H)‐thione 2 , these side‐products are the corresponding 1,3‐thiazol‐5(4H)‐one 5 and the 1 : 2 adduct 8 (Schemes 2 – 4). Their formation can be rationalized by the decomposition of the initially formed spirocyclic 1,3‐oxathiolane and by a second addition onto the C=N bond of the 1 : 1 adduct, respectively. The secondary epimerization by inversion of the configuration of the spiro‐C‐atom (Schemes 5 – 7) can be explained by a Lewis‐acid‐catalyzed ring opening of the 1,3‐oxathiolane ring and subsequent ring closure to the thermodynamically more stable isomer (Scheme 12). In the case of 2,2,4,4‐tetramethyl‐3‐thioxocyclobutanone ( 20 ), apart from the expected spirocyclic 1,3‐oxathiolanes 21 and 23 , dispirocyclic 1 : 2 adducts were formed by a secondary addition onto the C=O group of the four‐membered ring (Schemes 9 and 10).     

1,3‐Dimethyl­isoguanine

The structure of 1,3‐dimethyl­isoguanine [or 6‐amino‐1,3‐dimethyl‐1H‐purin‐2(3H)‐one], C₇H₉N₅O, has been redetermined and the correct assignment of H atoms on the heterocycle is now reported. Inter­molecular hydrogen‐bonding inter­actions confirm that this form is the correct mol­ecular structure; this form is also in agreement with an earlier reported structure of the trihydrate form.     

A convenient one‐pot synthesis of new 3‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐ones

Anhydrous zinc bromide catalysed reactions of arylidine‐3‐acetyl coumarins ( 1a‐c ) and 5,6‐benzoanalogs of arylidine 3‐acetyl coumarins ( 4a,4b ) with 1,3‐cyclohexanedione gives ‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2yl)‐2H‐chromen‐2‐ones ( 3a, 3c ) and 5,6‐benzoanalogs of 3‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2yl)‐2H‐chromen‐2‐one ( 5a,5b ). Under similar conditions arylidine‐3‐acetylcoumarins ( 1a, 1b,1d, 1e, 1f ) and 5,6‐benzoanalog of arylidine 3‐acetyl coumarin ( 4b ) react with 5,5‐dimethyl‐1,3‐cyclohexanedione (dimedone) yielding 3‐(4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐ones ( 3d‐3h ) and the 5,6‐benzoanalog of 3.(4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐one ( 5c ).     

Regioselective 1,3‐Dipolar Cycloadditions of (1Z)‐1‐(Arylmethylidene)‐5,5‐dimethyl‐3‐oxopyrazolidin‐1‐ium‐2‐ide Azomethine Imines to Acetylenic Dipolarophiles

The 5,5‐dimethylpyrazolidin‐3‐one ( 4 ), prepared from ethyl 3‐methylbut‐2‐enoate ( 3 ) and hydrazine hydrate, was treated with various substituted benzaldehydes 5a – i to give the corresponding (1Z)‐1‐(arylmethylidene)‐5,5‐dimethyl‐3‐oxopyrazolidin‐1‐ium‐2‐ide azomethine imines 6a – i . The 1,3‐dipolar cycloaddition reactions of azomethine imines 6a – h with dimethyl acetylenedicarboxylate (=dimethyl but‐2‐ynedioate; 7 ) afforded the corresponding dimethyl pyrazolo[1,2‐a]pyrazoledicarboxylates 8a – h , while by cycloaddition of 6 with methyl propiolate (=methyl prop‐2‐ynoate; 9 ), regioisomeric methyl pyrazolo[1,2‐a]pyrazolemonocarboxylates 10 and 11 were obtained. The regioselectivity of cycloadditions of azomethine imines 6a – i with methyl propiolate ( 9 ) was influenced by the substituents on the aryl residue. Thus, azomethine imines 6a – e derived from benzaldehydes 5a – e with a single substituent or without a substituent at the ortho‐positions in the aryl residue, led to mixtures of regioisomers 10a – e and 11a – e . Azomethine imines 6f – i derived from 2,6‐disubstituted benzaldehydes 5f – i gave single regioisomers 10f – i .     

2,2‐Dimethyl‐5‐nitroso‐1,3‐dioxan‐5‐yl benzoate, 2,2‐dimethyl‐5‐nitroso‐1,3‐dioxan‐5‐yl 4‐chlorobenzoate and 5‐nitroso‐1,3‐dioxan‐5‐yl 4‐chlorobenzoate

The crystal structures of 2,2‐dimethyl‐5‐nitroso‐1,3‐dioxan‐5‐yl benzoate, C₁₃H₁₅NO₅, (I), 2,2‐dimethyl‐5‐nitroso‐1,3‐dioxan‐5‐yl 4‐chlorobenzoate, C₁₃H₁₄ClNO₅, (II), and 5‐nitroso‐1,3‐dioxan‐5‐yl 4‐chlorobenzoate, C₁₁H₁₁NO₅, (III), have been determined in order to gain insight into the conformational preference of α‐benzoyloxynitroso. Unfavourable 1,3‐diaxial interactions force (I) and (II) to crystallize in the 2,5 twist‐boat conformation, whereas compound (III), lacking this destabilizing interaction, crystallizes in the chair conformation.     

Synthesis and Structures of Arene Ruthenium (II)–NHC Complexes: Efficient Catalytic α‐alkylation of ketones via Hydrogen Auto Transfer Reaction

A panel of six new arene Ru (II)‐NHC complexes 2a‐f , (NHC = 1,3‐diethyl‐(5,6‐dimethyl)benzimidazolin‐2‐ylidene 1a , 1,3‐dicyclohexylmethyl‐(5,6‐dimethyl)benzimidazolin‐2‐ylidene 1b and 1,3‐dibenzyl‐(5,6‐dimethyl)benzimidazolin‐2‐ylidene 1c ) were synthesized from the transmetallation reaction of Ag‐NHC with [(η⁶‐arene)RuCl₂]₂ and characterized. The ruthenium (II)‐NHC complexes 2a‐f were developed as effective catalysts for α‐alkylation of ketones and synthesis of bioactive quinoline using primary/amino alcohols as coupling partners respectively. The reactions were performed with 0.5 mol% catalyst load in 8 h under aerobic condition and the maximum yield was up to 96%. Besides, the different alkyl wingtips on NHC and arene moieties were studied to differentiate the catalytic robustness of the complexes in the transformations.     

The mixed diol–dithiol 2,2‐bis(sulfanylmethyl)propane‐1,3‐diol: characterization of key intermediates on a new synthetic pathway

A new synthetic route to 2,2‐bis(sulfanylmethyl)propane‐1,3‐diol, (II), is described starting from the commercially available 2,2‐bis(hydroxymethyl)propane‐1,3‐diol. The structures of two intermediates on this route are described. 5,5‐Dimethenyl‐2,2‐dimethyl‐1,3‐dioxane bis(thiocyanate) (systematic name: {[5‐(cyanosulfanyl)‐2,2‐dimethyl‐1,3‐dioxan‐5‐yl]sulfanyl}formonitrile), C₁₀H₁₄N₂O₂S₂, (X), crystallizes in the space group P2₁/c with no symmetry relationship between the two thiocyanate groups. There is a short intramolecular N...S contact for one thiocyanate group, while the second group is positioned such that this type of interaction is not possible. 1,3‐(Hydroxymethyl)propane‐1,3‐diyl bis(thiocyanate), C₇H₁₀N₂O₂S₂, (XI), also features a single short N...S contact in the solid state. Hydrogen bonding between two molecules of compound (XI) results in the formation of dimers in the crystal, which are then linked together by a second hydrogen‐bond interaction between the dimers. In addition, the structures of two intermediates from an unsuccessful alternative synthesis of (II) are reported. 2,2‐Bis(chloromethyl)propane‐1,3‐diol, C₅H₁₀Cl₂O₂, (VI), crystallized as an inversion twin with a minor twin fraction of 0.43 (6). It forms a zigzag structure as a result of intermolecular hydrogen bonding. The structure of 9,9‐dimethyl‐2,4,8,10‐tetraoxa‐3λ⁴‐thiaspiro[5.5]undecan‐3‐one, C₈H₁₄O₅S, (VII), shows evidence for a weak S...O contact with a distance of 3.2529 (11) Å.     

Asymmetric Reaction of Simple Nitro Compounds with Chiral 1,3‐Oxazolidin‐2‐ones

The chiral oxazolidinone 1 (=[(3aS,6R,7aR)‐tetrahydro‐8,8‐dimethyl‐2‐oxo‐4H‐3a,6‐methano‐1,3‐benzoxazol‐3‐yl](oxo)acetaldehyde) was found to react stereoselectively with simple nitro compounds in the presence of Al₂O₃ or Bu₄NF?3 H₂O (TBAF) as catalysts, affording the diastereoisomeric nitro alcohols 3 – 6 with good asymmetric induction. When Al₂O₃ was used, the (S)‐configuration at the center bearing the OH group was generated, with the relative syn‐configuration for the major diastereoisomers. In the case of the nitro‐aldol reaction catalyzed by TBAF, an opposite asymmetric induction was found for two nitro compounds. In contrast to 1 , compound 12 (=((4R,5S)‐4‐methyl‐2‐oxo‐5‐phenyl‐1,3‐oxazolidin‐3‐yl)(oxo)acetaldehyde), a derivative of Evans auxiliary, gave rise to poor asymmetric induction in Henry reactions.     

2,3:4,6‐Di‐O‐isopropylidene‐α‐l‐sorbofuranose and 2,3‐O‐isopropylidene‐α‐l‐sorbofuranose

In the title compounds, C₁₂H₂₀O₆, (I), and C₉H₁₆O₆, (II), the five‐membered furanose ring adopts a ⁴T₃ conformation and the five‐membered 1,3‐dioxolane ring adopts an E₃ conformation. The six‐membered 1,3‐dioxane ring in (I) adopts an almost ideal ^OC₃ conformation. The hydrogen‐bonding patterns for these compounds differ substantially: (I) features just one intramolecular O—H...O hydrogen bond [O...O = 2.933 (3) Å], whereas (II) exhibits, apart from the corresponding intramolecular O—H...O hydrogen bond [O...O = 2.7638 (13) Å], two intermolecular bonds of this type [O...O = 2.7708 (13) and 2.7730 (12) Å]. This study illustrates both the similarity between the conformations of furanose, 1,3‐dioxolane and 1,3‐dioxane rings in analogous isopropylidene‐substituted carbohydrate structures and the only negligible influence of the presence of a 1,3‐dioxane ring on the conformations of furanose and 1,3‐dioxolane rings. In addition, in comparison with reported analogs, replacement of the –CH₂OH group at the C1‐furanose position by another group can considerably affect the conformation of the 1,3‐dioxolane ring.     

Unexpected Formation of Dimethylthioketene Cycloadducts in the Reaction of 1,3‐Diphenylaziridine‐2,2‐dicarboxylate with Cyclobutanethione Derivatives

The reaction of 2,2,4,4‐tetramethyl‐3‐thioxocyclobutanone ( 1 ) with cis‐1‐alkyl‐2,3‐diphenylaziridines 5 in boiling toluene yielded the expected trans‐configured spirocyclic 1,3‐thiazolidines 6 (Scheme 1). Analogously, dimethyl trans‐1‐(4‐methoxyphenyl)aziridine‐2,3‐dicarboxylate (trans‐ 7 ) reacted with 1 and the corresponding dithione 2 , respectively, to give spirocyclic 1,3‐thiazolidine‐2,4‐dicarboxylates 8 (Scheme 2). However, mixtures of cis‐ and trans‐derivatives were obtained in these cases. Unexpectedly, the reaction of 1 with dimethyl 1,3‐diphenylaziridine‐2,2‐dicarboxylate ( 11 ) led to a mixture of the cycloadduct 13 and 5‐(isopropylidene)‐4‐phenyl‐1,3‐thiazolidine‐2,2‐dicarboxylate ( 14 ), a formal cycloadduct of azomethine ylide 12 with dimethylthioketene (Scheme 3). The regioisomeric adduct 16 was obtained from the reaction between 2 and 11 . The structures of 6b , cis‐ 8a , cis‐ 8b, 10 , and 16 have been established by X‐ray crystallography.     

Oxidation of 7,8‐diaminotheophylline with lead tetraacetate and reaction of the oxidation product, 6‐cyanoimino‐5‐diazo‐1,3‐dimethylpyrimidine‐2,4‐dione with alcohols or amines

Oxidation of 7,8‐diaminotheophylline (1) with lead tetraacetate in refluxing toluene gave a mixture of 3‐amino‐5,7‐dimethylpyrimido[4,5‐e][1,2,4]triazine‐6,8‐dione ( 2 ) and 6‐cyanoimino‐5‐diazo‐1,3‐dimethylpyrimidine‐2,4‐dione ( 4 ). The latter was transformed to 2 by the reaction with 1‐propanethiol in quantitative yield. The reaction of 4 with methanol, ethanol and 1‐propanol in the presence of rhodium ( II ) acetate gave 5‐alkoxy‐6‐(2‐alkyl‐3‐isoureido)‐1,3‐dimethylpyrimidine‐2,4‐diones ( 7a‐c ). A similar reaction of 4 with alkylamines such as n‐propylamine, n‐butylamine, isobutylamine and n‐hexylamine gave a mixture of 7‐alkyl‐8‐aminotheophyllines ( 8a‐d ) and (5‐alkylamino‐1,3‐dimethyl‐2,4‐dioxopyrimidin‐6‐yl)cyanamides ( 9a‐d ).     

Hydriodic Acid‐Mediated Cyclization of α‐Substituted Secondary 2‐Ethenylbenzamides: Synthesis of 2‐Substituted 2,3‐Dihydro‐3,3‐dimethyl‐1H‐isoindol‐1‐ones and 3,3‐Disubstituted (E)‐1‐(Arylimino)‐1,3‐dihydroisobenzofurans

A new and facile method for the preparation of 2‐substituted 2,3‐dihydro‐3,3‐dimethyl‐1H‐isoindol‐1‐ones 3 and 3,3‐disubstituted (E)‐1‐(arylimino)‐1,3‐dihydroisobenzofurans 6 has been developed. Thus, treatment of N‐alkyl(or aryl)‐2‐(1‐methylethen‐1‐yl)benzamides 2 with concentrated hydriodic acid (HI) in MeCN at room temperature afforded 3 . Similar treatment of N‐aryl‐2‐(1‐phenylethen‐1‐yl)benzamide 5 with concentrated HI at 0° afforded 6 .     

Conformational Studies of (±)‐11,12‐Didehydro‐11‐deoxycorynoline and (+)‐11,13‐Didehydro‐11‐deoxychelidonine,Hexahydrobenzo[c]phenanthridine‐Type Alkaloid Derivatives,by X‐Ray Crystal Structure and NMR Analyses

The X‐ray crystal analyses of the two 11‐deoxy‐didehydrohexahydrobenzo[c]phenanthridine‐type alkaloid derivatives 3 and 4 , derived from (±)‐corynoline ( 1 ) and (+)‐chelidonine ( 2 ), established their structures as (±)‐(5bRS,12bRS)‐5b,12b,13,14‐tetrahydro‐5b,13‐dimethyl[1,3]benzodioxolo[5,6‐c]‐1,3‐dioxolo[4,5‐i]phenanthridine ( 3 ) and (+)‐rel‐(12bR)‐7,12b,13,14‐tetrahydro‐13‐methyl[1,3]benzodioxolo[5,6‐c]‐1,3‐dioxolo[4,5‐i]phenanthridine ( 4 ). The conformations of 3 and 4 in CDCl₃ were determined on the basis of ¹H‐ and ¹³C‐NMR spectroscopy.     

A convenient synthesis of pyrrolo‐annelated 1,3‐diselenole‐2‐thione and 1,3‐diselenol‐2‐one derivatives via dipyrrolo‐annelated 1,2,5,6‐tetraselenocine derivatives

The reaction of 2,5‐dimethyl‐3,4‐diselenocyanato‐1H‐pyrrole by NaBH₄ or NaOCH₃ led to tetraselenide 7 in quantitative yield. Treatment of protected tetraselenide 8 with LiAlH₄ afforded the aluminum complex intermediate that was converted into pyrrole‐annelated 1,3‐diselenolo‐2‐thione 9 in excellent yield. Similarly, treatment of tetraselenide 8 with LiAlH₄ followed by TFA afforded 1,2‐diselenol intermediate that was converted into pyrrole‐annelated 1,3‐diselenolo‐2‐one 10 upon treatment of diimidazole carbonate. J. Heterocyclic Chem., (2011).     

A zigzag‐type one‐dimensional coordination polymer formed by (2,2‐di­methyl‐1,3‐propane­di­amine)­bis­(iso­nico­tin­ato)­platinum(II) and copper nitrate

The title compound, catena‐poly­[[[tri­aqua‐2κ³O‐(2,2‐dimethyl‐1,3‐propane­di­am­ine)‐1κ²N,N′‐μ‐isonicotinato‐1:2κ²N:O‐copper(II)­plati­num(II)]‐μ‐isonicotinato‐2:1′κ²O:N] dinitrate], {[CuPt(C₆H₄NO₂)₂(C₅H₁₄N₂)(H₂O)₃](NO₃)₂}_n, obtain­ed from equimolar (dmpda)Pt^II(isonic)₂ (where dmpda is 2,2‐di­methyl‐1,3‐propane­di­amine and isonic is isonicotinate) and copper(II) nitrate, has been found to be a one‐dimensional coordination polymer of the zigzag‐type.