Structures of Halogen Substituted Boranes

Electrophilic alkylation of 1-SB9H9

“…Under similar conditions, Williams and coworkers were able to prepare and identify various alkyl-substituted products of decaborane- [2,3]. Several structural investigations indicate that the site of electrophilic substitution correlates with the site of highest electron density [4] in molecules such as Bi0H14 [5,6], 1,2-or 1,7-C,B1&iz [7] and 2,4-C2B5H, 181. In certain cases the initial electrophilic substitution in BloHlo2has been shown to occur contrary to predicted axial placement [9-111.…”

Azido/Tetrazole Tautomerism in 2‐Azidoadenine β‐D‐Pentofuranonucleoside Derivatives

“…The synthesis of 2-azidoadenosine (6) was carried out by a modification of Schaeffer's procedure. [5] In brief, a glycosylation reaction between 2,6-dichloropurine and commercially available 1-O-acetyl-2,3,5-tri-O-benzoylβ--ribose (1) with stannic chloride [8] as a catalyst gave the corresponding protected nucleoside, which upon treatment with methanolic ammonia afforded 2-chloroadenosine (2). This was converted into the 2-hydrazino derivative, which on treatment with sodium nitrite in an acid medium gave the first target molecule, 6.…”

“…Solvents were dried and distilled prior to use and solids were dried with P 2 O 5 under reduced pressure. [5] M.p. (from ethanol) 145Ϫ147°C (ref.…”

“…[3] 200Ϫ205°C). [5] Compound 2 (0.296 g, 0.98 mmol) was added to a solution of hydrazine monohydrate (5 mL). The reaction mixture was stirred at room temperature for 16 h. The solution was diluted with 2-propanol and the solvents were evaporated to dryness.…”

“…As a part of our ongoing research program on this topic, we have synthesized various β--pentofuranonucleoside derivatives bearing 2-azidoadenine as the base. The first synthesis of 2azidoadenosine (6) was reported in 1958, [5] while the synthesis of 2-azido-2Ј-deoxyadenosine (7) was described during the course of our studies, [6] although no antiviral evaluation was reported. We thus decided to undertake the synthesis of the β--ribofuranoside derivative of 2-azidoadenine and its 2Ј-deoxy-, 2Ј,3Ј-dideoxy-and 2Ј,3Ј-dideoxy-2Ј,3Ј-didehydro counterparts in order to perform the antiviral evaluation of the whole series.…”