bluuebunny/crossref_metadata_2025_split huggingface dataset:
(R,R)‐2,3‐Butanediol and (s)‐pinanediol allylboronates in chiral synthesis of (2S,3S)‐3‐methyl‐5‐hexen‐2‐ol
Authors: Matteson Donald S. , Campbell J. Douglas 
Published: January 2005

Abstract(R,R)‐Butanediol (dichloromethyl)boronate (1) with 1 equiv. allylmagnesium halide yields (R,R)‐2,3‐butanediol (1S)‐(1‐chloro‐3‐butenyl)boronate (3) together with the diallylated product (R,R)‐2,3‐butanediol (1‐allyl‐3‐butenyl)boronate (4). The formation of 4 is unprecedented in reactions of α‐chloroboronic esters with Grignard reagents. With methylmagnesium bromide 3 yielded (R,R)‐2,3‐butanediol (1S)‐(1‐methyl‐3‐butenyl)boronate (5), which failed to hydrolyze with water. Hydrolysis of 3 yielded impure α‐chloroboronic acid, which was esterified with pinacol and treated with methylmagnesium bromide to form 6, which with (dichloromethyl)lithium followed by methylmagnesium bromide yielded diastereomeric boronic esters 7 and 8. Oxidation by hydrogen peroxide yielded (2S,3S)‐ and (2R,3S)‐3‐methyl‐5‐hexen‐2‐ol (9 and 10, ees unknown). Treatment of (s)‐pinanediol allylboronate (11) with (dichloromethyl)lithium at −100°C followed by zinc chloride at up to 25°C has proceeded in the normal way to form (s)‐pinanediol (1S)‐(1‐chloro‐3‐butenyl)‐boronate (12), which has been elaborated via 13, 14, and 15 to (2S,3S)‐3‐methyl‐5‐hexen‐2‐ol (9) in 95% de.
Reaction of the diisopropylaminochlorophosphenium cation with crotonaldehyde dimethylhydrazone and acetone azine
Authors: Arif Atta M. , Cowley Alan H. , Kren Robert M. , Westmoreland Donald L. 
Published: January 2005

AbstractThe phosphenium ion [(i‐Pr2N)CIP]+ (1) reacts with crotonaldehyde dimethylhydrazone (2) to afford a product with a C3NP ring system (4). The reaction of 1 with acetone azine (3) results in a novel tricyclic compound (6) which features a C2N2P2 and two C2N2P rings. The structures of 4 and 6 were established by X‐ray crystallography. Compound 4, C12H26AlCl3N3OP, crystallizes in the monoclinic space group P21/n with Z = 4, a = 15.400(6), b = 14.442(4), c = 9.206(3) Å, and β = 93.33(3)°. Compound 6, C12H22Al2Cl6N4O2P2, crystallizes in the triclinic group P1 with Z = 1, a = 8.556(1), b = 9.782(1), c = 8.119(1) Å, α = 94.48(1), β = 104.97(1), and γ = 78.35(1)°.
About the structure of phosphorus ylids: Electron distribution and geometry
Authors: Schlosser Manfred , Jenny Titus , Schaub Bruno 
Published: January 2005

AbstractUsing 13C‐chemical shifts as a probe for the electronic environment of carbon centers, triphenylphosphoniomethanide, the model case of a “reactive” phosphorus ylid, was found to have much more zwitterion than PC double bond character (resonance structure 1a being dominant). Triphenylphosphonio‐propenide (“triphenylphosphonium‐allylid”), a “moderated” ylid, accumulates electron excess mainly at the α‐carbon atom (resonance structure 6a being dominant) whereas triphenylphosphonio‐ethenoate (formyl‐methylene‐triphenylphosphorane) and other “stabilized” ylids carry roughly equal fractions of negative charge at the α‐carbon and the oxygen atom (resonance formulas a and b being of comparable importance). The one‐bond C,H coupling constant of triphenylphosphonio‐methanide (1) argues against a perfectly planar ylid center. The three‐bond P,C coupling constants permit the assignment of endo‐ or exo‐configurations to ylids having an allyl‐type side‐chain.
Stereochemistry in the reaction of alkylsulfinyl phenylmethyl carbanion with electrophiles
Authors: Higaki Masato , Goto Mutsuo , Ohno Atsuyoshi 
Published: January 2005

AbstractStereochemistry of the reactions of methyl‐, ethyl‐, 2‐propyl‐, and 1,1‐dimethylethylsulfinyl phenylmethyl carbanions with deuterium oxide and methyl iodide in tetrahydrofuran have been studied. The 2‐propylsulfinyl phenylmethyl carbanion exerts abnormal behavior in the sense that the alkyl substituent herein has no ability to freeze the conformation of the carbanion. The results are interpreted in terms of hard and soft interactions. 7Li and 17O nuclear magnetic resonance (NMR) spectroscopy revealed that the carbanions derived from these sulfoxides behave as the oxylate form.
[1,5] Sigmatropic shifts in a 1,4‐diphospholylbenzene
Authors: Mercier François , Mathey François 
Published: January 2005

AbstractThe central phenylene ring of 1,4‐bis(3,4‐dimethylphosphol‐1‐yl)benzene undergoes [1,5] shifts around both phospholyl rings above 150°C to give 1,4‐bis(3,4‐dimethyl‐5H‐phosphol‐2‐yl)benzene, which can be trapped by tolane, [CpFe(CO)2]2, or Mn2 (CO)10 to yield the corresponding bis‐1‐phosphanor‐bornadiene, bis‐phosphaferrocene, or bis‐phosphacymantrene respectively.
Ligand coupling of 2‐pyridyl sulfoxides having an sp2 stereocenter at the α‐position: A novel preparation of α‐stilbazoles
Authors: Wakabayashi S. , Kiyohara Y. , Kameda S. , Uenishi J. , Oae S. 
Published: January 2005

AbstractLigand coupling of (E)‐ and (Z)‐styryl 2‐pyridyl sulfoxides with methylmagnesium bromide gave (E)‐and (Z)‐2‐styrylpyridine, respectively in a stereospecific manner. A number of (E)‐2‐styrylpyridine derivatives were prepared by the coupling reaction. Methyl styryl sulfoxide and 2,2′‐bipyridyl were obtained as by‐products. The mechanism of the reaction is discussed based on quantitative analysis of the products.
A novel simple dethioacetalization of thioacetals and thioketals with t‐butyl thionitrite
Authors: Park Young Jun , Kim Yong Hae , Oae Shigeru 
Published: January 2005

AbstractThioacetals and thioketals were readily cleaved to carbonyl compounds in excellent yields by treatment with t‐butyl thionitrite at ca. 0°C in acetonitrile under mild conditions. The conversion of thioketals to the ketones appears to be initiated via nitrosation on two sulfur atoms of the thioketals, followed by intramolecular transfer of nitroso oxygen.
X‐ray structure of 3‐diphenylmethylene‐2‐(2,4,6‐tri‐t‐butylphenyl)thiaphosphirane 2‐sulfide: The first thiaphosphirane with exo‐methylene
Authors: Hirotsu Ken , Okamoto Akihiro , Toyota Kozo , Yoshifuji Masaaki 
Published: January 2005

AbstractThe title compound was prepared by sulfurization of a 1‐phosphaallene and its x‐ray structure analysis showed the following notable features of the thiaphosphirane ring: P‐S = 2.101(2), P‐C = 1.770(5) and S‐C = 1.767(5) Å (remarkably short), and ∠SPC = 53.5(2), ∠PSC = 53.6(2) and ∠PCS = 72.9(2)°.
Toxic organophosphorus esters hydrolysis enhanced by onium perborates
Authors: Cristau Henri‐Jean , Torreilles Eliane , Ginieys Jean‐François 
Published: January 2005

AbstractThe addition of equimolecular quantities of phosphonium salts to an aqueous sodium perborate solution (Na+ PB−) greatly enhances he efficiency of Na+ PB− as a reagene that destroys organophosphorus esters, such as p‐nitrophenyldiethyl phosphate or ethyl p‐nitrophenyl methylphosphonate.
Pyrromethene–BF2 complexes as laser dyes:1.
Authors: Shah Mayur , Thangaraj Kannappan , Soong Mou‐Ling , Wolford Lionel T. , Boyer Joseph H. , Politzer Ieva R. , Pavlopoulos Theodore G. 
Published: January 2005

AbstractCondensations between 3‐X‐2,4‐dimethylpyrroles (X = H, CH3, C2H5, and CO2C2H5) and acyl chlorides gave derivatives of 3,5,3′,5′‐tetramethylpyrromethene (isolated as their hydrochloride salts): 6‐methyl, 6‐ethyl, 4,4′,6‐trimethyl, 4,4′‐diethyl‐6‐methyl, and 4,4′‐dicarboethoxy‐6‐ethyl derivatives for conversion on treatment with boron trifluoride to 1,3,5,7‐tetramethylpyrromethene–BF2 complex (TMP–BF2) and its 8‐methyl (PMP–BF2), 8‐ethyl, 2,6,8‐trimethyl (HMP–BF2),2,6,‐diethyl‐8‐methyl (PMDEP–BF2), and 2,6‐dicarboethoxy‐8‐ethyl derivatives. Chlorosulfonation converted, 1,3,5,7,8‐pentamethylpyrromethene–BF2 complex to its 2,6‐disulfonic acid isolated as the lithium, sodium (PMPDS–BF2), potassium, rubidium, cesium, ammonium, and tetramethylammonium disulfonate salts and the methyl disulfonate ester. Sodium 1,3,5,7‐tetramethyl‐8‐ethylpyrromethene‐2,6‐disulfonate–BF2 complex was obtained from the 8‐ethyl derivative of TMP–BF2. Nitration and bromination converted PMP–BF2 to its 2,6‐dinitro‐(PMDNP–BF2) and 2,6‐dibromo‐ derivatives. The time required for loss of fluorescence by irradiation from a sunlamp showed the following order for P–BF2 compounds (10−3 to 10−4 M) in ethanol: PMPDS–BF2, 7 weeks; PMP–BF2, 5 days; PMDNP–BF2, 72 h; HMP–BF2, 70 h; and PMDEP–BF2, 65 h. Under similar irradiation PMPDS–BF2 in water lost fluorescence after 55 h. The dibromo derivative was inactive, but each of the other pyrromethene–BF2 complexes under flashlamp excitation showed broadband laser activity in the region λ 530–580 nm. In methanol PMPDS–BF2 was six times more resistant to degradation by flashlamp pulses than was observed for Rhodamine‐6G (R‐6G). An improvement (up to 66%) in the laser power efficiency of PMPDS–BF2 (10−4 M in methanol) in the presence of caffeine (a filter for light <300 nm) was dependent on flashlamp pulse width (2.0 to 7.0 μsec).
Complexes of tricoordinate hypervalent pnictogens with pentamethylcyclopentadienylruthenium
Authors: Arduengo Anthony J. , Lattman Michael , Calabrese Joseph C. , Fagan Paul J. 
Published: January 2005

AbstractThe complexes of a pentamethylcyclopentadienylruthenium moiety with hypervalent tricoordinate pnictogens are reported. A unique mode of complexation is observed for each of the different pnictogens (P, As, Sb). The phosphorus derived complex exhibits an 8‐electron tetrahedral bonding environment at phosphorus. The antimony derived complex maintains a 10‐electron bonding system at antimony with a pseudo‐trigonalbipyramidal geometry at antimony. The arsenic‐containing complex is formed with destruction of the original arsenic heterocycle and formation of a trinuclear Ru–Ru–As ring. Remarkably, the formation of the arsenic ruthenium complex can be reversed to reconstruct the original arsenic heterocycle.
Selenium‐Catalyzed debromination of vic‐dibromoalkanes and α‐bromo ketones with carbon monoxide and water
Authors: Nishiyama Yutaka , Katsuen Susumu , Jounen Hiroshi , Hamanaka Sawako , Ogawa Akiya , Sonoda Noboru 
Published: January 2005

AbstractSelenium has been found to be an excellent catalyst for the reductive debromination of some organic bromides with carbon monoxide and water: vic‐dibromoalkanes and α‐halo ketones can be reduced to the corresponding alkenes and ketones respectively in moderate to high yields.
Synthesis of dimeric 1,3,2λ5‐benzoxazaphospholes from phosphinic acid derivatives by silylation/desiloxylation
Authors: Bovin Alexander N. , Yarkevich Alla N. , Tsvetkov Eugene N. 
Published: January 2005

AbstractThe reaction of N,N,O‐tris(trimethylsilyl)‐o‐aminophenol with two equivalents of phosphinic chloride yielded dimeric 2,2‐disubstituted 1,3,2λ5‐benzoxazaphospholes and trimethylsilyl phosphinate. The chlorides having the bulk substituents (o‐chlorophenyl or tert‐butyl) at phosphorus or containing PN and PO bonds (instead of a PC bond) either didn't react at all or reacted to retain the phosphoryl group. Being stable in solution at 20°C, the individual diastereoisomers of dimeric 1,3,2‐benzoxazaphospholes were converted upon warming to an equilibrium mixture of isomers. When reacted with another dimer each gave a mixed dimeric compound having two different phosphorus atoms in the molecule.
Bis(diisopropylamino)phosphanyldiazomethane: A building block for the synthesis of stable carbene and nitrilimines
Authors: Bertrand Guy 
Published: January 2005

AbstractThermolysis of [bis(diisopropylamino)phosphanyl](trimethylsilyl)diazomethane 1 affords the corresponding carbene 2, which is stable enough to be spectroscopically characterized. This species possesses a phosphorus–carbon multiple‐bond character as shown by the 2 + 3 and 2 + 2 cycloaddition reactions observed with trimethylsilyl azide or N2O and ethyl cyanoformate, respectively. On the other hand, 2 undergoes all the classical reactions of a carbene: cyclopropanation reaction with electron‐poor alkenes, carbon–hydrogen bond insertion, and carbene–carbene coupling with isonitriles. Compound 2 reacts with trimethylsilyl triflate affording a stable methylenephosphonium salt 15. Treatment of the lithium salt of the [bis(diisopropylamino)thiophosphoranyl]diazomethane 18 with the bis(diisopropylamino)phosphanyl chloride leads to a stable nitrilimine 3. Thermolysis of 3 affords the isomeric diazo derivative 20, while photolysis gives rise to thiophophoranylnitrile 21 and cyclodiphosphazene 23. Regioselective 2 + 3 cycloadditions are observed with electron‐poor dipolarophiles. Addition of trimethylsilyl triflate to 3 leads to a stable electrophilic nitrilimine 29.
Polyazaphosphorus macrocycles: Synthesis, reactivity, complexation
Authors: Majoral Jean‐Pierre , Badri Meryam , Caminade Anne‐Marie 
Published: January 2005

AbstractA general synthesis of various polyazaphosphorus macrocycles involving [1 + 1], [2 + 2], or [3 + 3] cyclocondensations is reviewed, as well as the attempted synthesis of cryptands. Selective reduction (imino functions) methylation (PS groups), silylation (PO groups) are reported. Preparations of some macrocycle complexes are described.
Chemistry of the 2,3‐oxaphosphabicyclo[2.2.2]octene ring system: Extrusion of metaphosphates
Authors: Quin Louis D. , Bodalski Ryszard , Jankowski Stefan , Quin GyöOungyi S. , Sadanani Narayan D. , Wu Xiao‐Ping 
Published: January 2005

AbstractThe 2,3‐oxaphosphabicyclo[2.2.2]octene 3‐oxide (or sulfide) ring system is of considerable value because it easily fragments on being heated or irradiated (254 nm) to provide three‐coordinate phosphoryl species. The system is synthesized by O‐insertion with peracids into a CP bond of 7‐phosphanorbornene derivatives with a variety of P‐substituents. With rare exception, the insertion has been found to proceed with retention of the configuration at phosphorus, as established by X‐ray and NMR techniques. The thermal fragmentation that produces the metaphosphate derivatives EtOPO2, EtOP(S)O, and Et2NPO2 follows first‐order kinetics, and is independent of the concentration of a trapping agent for these species. Solvent effects and activation parameters join in defining a retrocycloaddition mechanism that ejects the free metaphosphate. The species PhPO2 can also be easily generated either thermally or photochemically. Metaphosphates have been found to attack ethereal oxygen in epoxides and oxetanes, and may undergo anchimeric participation with a properly placed methoxy group on the substituent used in the 2,3‐oxaphosphabicyclo[2.2.2]octene precursor.
Optically active phosphine oxides: 10 [1]; X‐ray structure and conformation of (Sp)‐ and (Rp)‐L‐menthyl α‐(phenylvinylphosphinyl)acetates
Authors: Pietrusiewicz K. Michał , Zabłocka Maria , KuoáZnikowski Maciej , Wieczorek Wanda , Maniukiewicz Waldemar , Rospenk Maria 
Published: January 2005

AbstractThe structures and solid‐state stereochemistry of the two P‐epimeric compounds (1 and 2) formed in a reaction of butyl phenylvinylphosphinite with (‐)‐L‐menthyl bromoacetate were studied by X‐ray crystallography and CP–MAS 13C NMR spectroscopy. The two compounds were also analyzed in solution by means of 2D 1H NMR, 13C NMR, IR, UV, and dipole moment measurement techniques. Compound 1, C20H29O3P, crystallized in the orthorhombic group P 212121 with Z = 4, a = 20.491(2), b = 16.719(1), and c = 5.910(1). Compound 2, C20H29O3P, crystallized in the monoclinic space group P 21 with Z = 2, a = 9.266(1), b = 9.852(1), c = 10.954(1), and β = 95.20(1)°. In the crystals both compounds possess their CCPO fragments in an s‐cis array, and have their PO and CO dipoles oriented uniformly in a syn, nearly parallel, fashion. In solution, however, an anti arrangement of these two dipoles is slightly preferred.
Synthesis of glycosyl phosphonates and related compounds
Authors: Vasella Andrea , Baudin Gisèle , Panza Luigi 
Published: January 2005

AbstractThe synthesis of glycosylphosphonates, isopolar, nonisosteric analogues of glycosylphosphates, from halonitro ethers, glycosyl acetates, or glycosyl trichloroacetimidates is reviewed. A new approach to phosphonate analogues of myo‐inositol trisphosphate (50) is described. Based on a hypothetical reaction mechanism for the formation of thioethers from a glyoxalase I inhibitor, an advanced intermediate 59 for the synthesis of diphosphonate–phosphate analogues of 50 is obtained by an addition–elimination–addition sequence from 54. Finally, glucosylphosphines, characterized as the corresponding phosphine oxides 61 and 62 have been prepared from the glycosylidene diazirine 60, a precursor of the tetra‐O‐benzylglucopyranosylidene carbene. The phosphine oxides 61 and 62 were also obtained by reaction of the glycosyl acetate 18 with methyl diphenylphosphinite.
Synthesis of antisense oligodeoxyribonucleotide analogues by use of deoxyribonucleoside 3′‐bis(1, 1, 1, 3,3,3‐hexafluoro‐2‐propyl) phosphites as new key intermediates
Authors: Hosaka Hideo , Watanabe Testuo , Suzuki Yoshikazu , Takaku Hiroshi 
Published: January 2005

AbstractThe deoxyribonucleoside 3′‐bis(1,1,1,3,3,3‐hexafluoro‐2‐propyl) phosphite units (3) are used in the chemical synthesis of oligodeoxyribonucleotides on solid supports. The new phosphite units (3) were prepared easily by reaction of nucleosides and tris‐(1,1,1,3,3,3‐hexafluoro‐2‐propyl) phosphite (2). They are readily activated by N‐methylimidazole under very mild conditions on a solid support. This operation involves a one step reaction, which is an advantage over both the phosphite and H‐phosphonate approaches. The use of deoxyribonucleoside phosphite intermediates in the synthesis of antisense oligodeoxyribonucleotides is also described.
Iminophosphanes as pseudocarbenes: A theoretical study of product formation
Authors: Schoeller Wolfgang W. , Busch Thilo , Niemann Jürgen , Dabisch Thomas , Stohrer W.‐D. 
Published: January 2005

AbstractP(III) double bond systems possess two closely spaced frontier orbitals, a π‐orbital and a σ‐orbital. In the parent iminophosphane the orbital sequence is σ (HOMO) and π* (LUMO). Thus, it is isolabal to a singlet carbene and undergoes self‐dimerization via a [2 + 1] cycloaddition. The resulting three membered ring system can be considered as a complex of two iminophosphanes. Contrary to the classical cyclopropanation reaction, in the pseudo‐carbene iminophosphane the corresponding [2 + 1] reaction is only slightly exothermic, as established by ab initio calculations at the SCF/CEPA‐1 and the MCSCF/ACPF level.
Role of the conformation in the reactivity of 1,3‐diphosphapropenes
Authors: Gouygou Maryse , Koenig Max , Escudié Jean , Couret Claude 
Published: January 2005

AbstractThe symmetrical and unsymmetrical 1,3‐diphospha‐propenes 3 and 4 were obtained from the corresponding diposphiranes 1 and 2. The chemical behavior of these compounds has been studied. Phosphonium‐phosphaalkenes 7a and 10a have been obtained in the reactions with aluminium trichloride. Whereas the symmetrical diphosphaallene 13 can be obtained by reaction of 1 or 3 with lithio compounds, the unsymmetrical diphosphaalene 14 cannot be prepared by a similar route. Reduction of 3a and 4a (obtained with a different conformation) by lithium aluminum hydride afforded phosphino‐phosphaalkenes 17a and 18a (with a similar conformation); further dehydrochlorination with amines led to the symmetrical and unsymmetrical diphosphaalenes 13 and 14, respectively. The formation of allenes strongly depends on the conformation of the starting diphosphapropenes.
Use of 1,3‐diphosphacyclobutadiene complexes in the synthesis of mixed metal aggregates containing cobalt, rhodium, and platinum: Structure of a hexarhodium complex
Authors: Hitchcock Peter B. , Maah Mohd Jamil , Nixon John F. 
Published: January 2005

AbstractThe η4‐diphosphacyclobutadiene complexes [M(η5‐C5R5)(η4‐P2C2Bu)] (M  Co, Rh; R  H, Me), react with Rh(I), Pt(O), and Pt(II) centers via the phosphorus lone paris of the rings of afford mixed metal complexes. The crystal and molecular structure of the novel hexarhodium complex [Rh2Cl2{Rh(P2C2Bu)}]4 (Cp  N5‐C5H5) is presented and discussed.
Diels‐Alder adducts of 4‐chloro‐1,6‐dihydrophosphinine derivatives: A new precursor of 2‐phosphapropene
Authors: Quin Louis D. , Tang Jian‐Sheng , Keglevich György 
Published: January 2005

AbstractThe 4‐chloro‐1,6‐dihydrophosphinine derivatives, prepared as a mixture of 3‐ and 5‐methyl isomers from the thermolysis of dichlorocarbene adducts with 1‐R‐3‐methylphospholene oxide (R  Me, MeO, EtO, n‐PrO, i‐PrO), participate in Diels‐Alder reactions with dimethyl acetylenedicarboxylate and N‐phenylmaleimide. The former reactant is of special value since the 2‐phosphabicyclo[2.2.2]octa‐5,7‐diene framework is thermally labile and undergoes retrocycloaddition by a different path, eliminating the CP bridging unit as a low‐coordinate species. Thus, in the case of R  Me, the initial phosphine oxides (a mixture of isomers) have been reduced to the phosphines and these undergo straightforward fragmentations on heating at 50°C to produce 2‐phosphapropene. The reactions of this transient species with water and alcohols have been investigated. Unlike the case of stabilized phosphaalkenes, hydration occurs smoothly without catalysis to produce Me2P(O)H; addition of alcohols gives phosphinites, Me2POR. The structure of the Diels‐Alder adducts was confirmed by 31P, 1H, and 13C NMR spectroscopy. Each of the isomeric 1,6‐dihydrophosphinine oxides gives two diastereomeric adducts; partial separation of some of the resulting four‐component mixtures was achieved with silica gel chromatography.
Dense compounds of C, H, N, and O atoms: Nitramine derivatives of diimino‐ and dioxodecahydro‐1 h,5h‐diimidazo‐[4,5‐b:4′,5′‐e]pyrazine
Authors: Vedachalam Murugappa , Ramakrishnan Vayalakkavoor T. , Boyer Joseph H. 
Published: January 2005

AbstractGuanidine condensed with 1,4‐diformyl‐2,3,5,6‐tetrahydroxypiperazine 1 to give 2,6‐diiminodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]pyrazine 3 isolated as the tetrahydrochloride salt. nitric acid (100%) at −40°C converted the bisguanidine 3 to 2,6‐dinitrimino‐4,8‐dinitrodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]‐ pyrazine 8 isolated as a dihydrate, whereas nitration by nitronium tetrafluoroborate at 0° to 25°C afforded 2,6‐diimino‐4,8‐dinitrodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]pyrazine 9 isolate as the monohydrated bistetrafluoroborate salt, and treatmetn with nitric acid (100%) and acetic anhydride or phosphorus pentoxide converted the bisguanidine 3 to 2,6‐dioxo‐1,3,4,5,7,8‐hexanitrodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐e]pyrazine 4, also obtained from the tetra N‐nitro compound 8 · 2 H2O and from the dinitramine 9 · 2 BHF4 · H2O after similar treatment. The cis‐syn‐cis‐ configuration of the tricyclic bisurea 4 and bisguanidine 9 was confirmed by X‐ray crys‐tallographic analysis. Nitrosation by nitrous acid or by dinitrogen tetroxide converted the bisguanidine 3 to a hydrated 2,6‐dinitrosimino‐4,8‐dinitrosodecahydro‐1H,5H‐diimidazo[4,5‐b:4′,5′‐]pyrazine 10 · 2.5 H2O, whereas treatment with nitrosonium tetrafluo‐roborate afforded the bistetrafluoroborate salt of 4,8‐dinitroso derivative 11 · 2 BHF 4. The nitrosamines 10 and 11 were converted to the tetranitro compound 8 · 2 H2O on treatment with nitric acid (100%) at −40°C. Treatmnt with fluoroboric acid etherate in acetonitrile converted nitroimino groups in compound 8 · 2 H2O and nitrosimino groups in compound 10 · 2.5 H2O to imino groups in compounds 9 · 2 BHF2 · H2O and 11 · 2 HBF4 respectively.