Alkyl Radical Initiated Cyclization/Cascade for Synthesizing Lactam-Substituted Alkyl Sulfones

An alkyl radical initiated cyclization/tandem reaction of alkyl bromides and alkyl electrophiles by using potassium metabisulphite(K_(2)S_(2)O_(5))as a connector is developed for the synthesis of various lactam-substituted alkyl sulfones.Notably,this process does not require a metal catalyst or metal powder reductant,highlighting its environmentally friendly features.The reaction demonstrates outstanding substrate adaptability and a high tolerance towards diverse functional groups.Furthermore,the biologically active molecules and commercially available drugs with a late-stage modification are also highly compatible with this transformation.Mechanistic studies revealed that the reaction proceeds through a single-step process involving intramolecular radical cyclization,"SO_(2)"insertion,and external alkyl incorporation.

Determination of genotoxic alkyl methane sulfonates and alkyl paratoluene sulfonates in lamivudine using hyphenated techniques

Two highly sensitive methods for the determination of genotoxic alkyl methane sulfonates (AMSs) and alkyl paratoluene sulfonates (APTSs) in lamivudine using hyphenated techniques have been presented. AMSs were determined by GC-MS method using GSBPINOWAX (30 m 0.25 mm 0.25 mm) column. Temperature program was set by maintaining at 100 1C initially for 3 min, then rised to 220 1C at the rate of 15 1C/min and maintained at 220 1C for 16 min. N,N-dimethyl formamide was used as diluent. APTSs were determined by LC-MS using Zorbax, Rx C8, 250 mm 4.6 mm, 5 mm column as stationary phase. 0.01 M ammonium acetate is used as buffer. The mixture of buffer and methanol in 75:25 (v/v) ratio was used as mobile phase A and mixture of buffer and methanol in 5:95 (v/v) ratio was used as mobile phase B. The gradient program (T/%B) was set as 0/28, 16/50, 17/100, 23/100, 27/28 and 40/28. Both the methods were validated as per International Conference on Harmonization guidelines. Limit of quantitation was found 1.5 mg/mL for AMSs and was in the range of 1.0-1.5 mg/mL for APTSs.

A STUDY ON THE DEGRADATION MECHANISM OF PHOTOCROSSLINKING PRODUCTS FORMED BY CYCLIZED POLYISOPRENE-DIAZIDE SYSTEM UNDER THE INFLUENCE OF ALKYL BENZENE SULFONIC ACIDS

The degradation mechanism of photocrosslinking products formed by cyclized polyisoprene-diazide system under the influence of the different alkyl benzene sulfonic acids was studied. The effects of alkyl chain length and the concentration of alkyl benzene sulfonic acids on the rate of degradation reaction were discussed. It was found that in the initial stage of degradation, the cyclicity ratio and the average fused ring number did not change considerably, but the percentage of uncyclized parts content varied significantly. The suitable mechanism was supposed.

Recent Development on Zero-Phosphate Spray Dried Detergent Powders Incorporated with Palm C16 Methyl Ester Sulfonates

Palm C16 methyl ester sulphonate （C16MES）is an anionic surfactant that has the potential as active ingredient in the production of laundry detergent powders. Although C16MES has been successfully applied in the production of high-density laundry detergent powders （HDDP）, it coulingd not be employed directly as it is in the spray drying process for the production of low-density laundry detergent powders （LDDP） without compromising the detergency and other significant properties. This research paper highlights the pilot-scale experimental study, which performed to produce phosphate-free laundry detergent （PFD） powders incorporated with binary anionic surfactants of C16MES and linear alkyl benzene sulphonic acid （LABSA）. Past laboratory experiments revealed that PFD powders resulted from C16MES/LABSA of 50：50 ratio and of pH 7-8 have good detergency stability upon one-week of continuous heating in an oven at 50~C with 85% relative humidity. Based on these laboratory results, subsequent experiments were carded in a 5 kg/hr capacity co-current pilot spray dryer using PFD formulations comprising six different ratios of C16MES/LABSA （0：100, 20：80, 40：60, 80：20 and 100：0） under the same pH condition. Three PFD formulations were selected for further evaluation based on their characteristics in the spray drying process. The cleaning properties and particle properties of the resulting spray dried detergent powders from these selected formulations were analyzed. Based on the overall evaluation, C16MES/LABSA in 40：60 ratio was selected as the ideal PFD formulation. Further tests confirmed that spray dried detergent powder （SDDP） from the ideal formulation has high level of biodegradability （60% in 13 d）, low eco-toxicity properties （LC50 of 11.3 mg/L） and moderate flowability charactedsUcs （Hausner ratio of 1.27 and Carr＇s index of 21.3）.

Transition-Metal-Free Reductive Cross-Coupling Employing Metabisulfite as a Connector:General Construction of Alkyl–Alkyl Sulfones

A multicomponent reductive cross-coupling of unactivated alkyl halides and alkyl tosylates connected via sodium metabisulfite was established for the general construction of alkyl-alkyl sulfones.Neither a metal catalyst nor a metal reductant is required in this“green”reductive cross-coupling.Inorganic sodium metabisulfite served as both the sulfur dioxide source and the robust connector.

A stereoselective synthesis of the C(3)-C(13) and C(14)-C(24) fragments of macrolactin A

Synthetic studies towards the C(3)-C(13) and C(14)-C(24) segments (3,4) of the potent antiviral and antitumor compound macrolactin A (1) are presented. Compound 3 was constructed via a convergent and facile approach, exploiting Wittig olefination to generate the sensitive E, Z-diene moiety. Compound 4 was synthesized from the chiral-pool derived sulfone 39a via an α-alkylation-desulfonation reaction sequence. Cu(II)-catalyzed coupling of a Grignard reagent with an allylic bromide and Julia olefination were also investigated for the preparation of compound 4.