Scandium triflate as an efficient and useful catalyst for the synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines under solvent-free conditions

A simple and efficient method has been developed for the synthesis of β-amino alcohols by ring opening of epoxides in the presence of a catalytic amount of Sc(OTf)₃ at room temperature under solvent-free conditions. The reaction works well with both aromatic and aliphatic amines. High regio-, and diastereoselectivity can be considered as a noteworthy advantage of this method.     

Novel TLC Densitometric Method for Quantification Of Solasodine in Various Solanum Species, Market Samples and Formulations

This paper describes a novel TLC densitometric method for the determination of solasodine in various Solanum species (Family Solanaceae). Solasodine does not give absorption in UV range. Hence, ion pair complex of solasodine and acid dye was spotted on TLC plates. A developing solvent with an organic acid ensured in situ color development of the complex which could be successfully quantified at 461 nm. Linearity was found to be in the range of 79.2–495 ng spot⁻¹ with correlation coefficient of 0.995. This method is reproducible, specific, eliminates post derivatization steps and the problem of background interference. The method was completely validated and applied to determine solasodine content in various herb samples, herb extract and their formulations. Accuracy of the method was found to be 98.54 ± 2.8%. No matrix interference was observed.     

Addition reactions of allyl stannanes to an indolo[2′,3′:3,4]pyrido[1,2‐b]isoquinoline imminium salt

The addition of organometallic reagents to the 13b‐position of the indolo[2′,3′:3,4]pyrido[1,2‐b]isoquinoline imminium salt 4 is described. Reaction of 4 with tetraallyl tin in 2‐methoxyethanol gave the allyl adduct 7 in moderate yield. Further elaboration of 7 yielded the pentacyclic benzylidene alcohols 13 and 14 . Structure elucidation of the compounds prepared was achieved by a combination of ¹H nmr spec troscopy and X‐ray crystallography.     

Synthesis of Functionalized Benzopyrans via Intramolecular 1,3-Dipolar Cycloaddition of Nitrile Oxides

Various functionalized benzopyran derivatives have been synthesized in good yields by a sequence of reactions viz. intramolecular cyclization of nitrile oxides, reductive cleavage, and acetylation.     

Development and validation of a sensitive ELISA for quantitation of Grastim (rhG-CSF) in rat plasma: Application to a pharmacokinetic study

Grastim is bacterially produced recombinant counterpart of human granulocyte colony stimulating factor (G-CSF). It has biological activity similar to that of endogenous G-CSF. In the present work a sensitive, accurate, precise and enzyme-linked immunosorbent assay (ELISA) for the quantitation of G-CSF in rat plasma was developed and validated. The ELISA method employed a technique in which anti-human-G-CSF was adsorbed onto 96-well maxisorp plates and used to capture the G-CSF in rat plasma samples. The captured G-CSF was then detected using streptavidin-HRP amplification system. Absolute recovery was >90% from rat plasma. The validation includes assessments of method accuracy and precision, range of reliable response, lower limit of quantitation (LLOQ), storage stability (30 days) in rat plasma and assay specificity. The standard curve for G-CSF was linear (R2 > 0.996) in the concentration range 4.88-625 pg/mL. The LLOQ was established at 4.88 pg/mL. The inter- and intra-day precisions in the measurement of quality control (QC) samples, 15, 250 and 500 pg/mL, were in the range 3.00-8.66% relative standard deviation (RSD) and 1.03-4.69% RSD, respectively. Accuracy in the measurement of QC samples was in the range 87.28-110.79% of the nominal values. The assay shows dilutional linearity and specificity. Stability of G-CSF was established for 30 days at -80 degrees C and through three freeze-thaw cycles. The validated assay was successfully employed for the assessment of pharmacokinetic disposition of G-CSF in rats.     

Chiral bis-Acetal Porphyrazines as Near-infrared Optical Agents for Detection and Treatment of Cancer

We report the preparation of chiral oxygen atom-appended porphyrazines (pzs) as biomedical optical agents that absorb and emit in the near-IR wavelength range. These pzs take the form M[pz(A_4-nB_n)], where “A” and “B” represent moieties appended to the pz’s pyrrole entities, A = (2R,3R) 2,3-dimethyl-2,3-dimethoxy-1,4-diox-2-ene, B = β,β′-di-isopropoxybenzo, M is the incorporated metal ion (M = H₂, Zn), and n = 0, 1, 2 (-cis/-trans) and 3 ( Scheme 1 ). When dissolved in polar media, H₂[pz(trans-A₂B₂)] 5a does not fluoresce and has a negligible quantum yield for singlet oxygen generation (Ф_Δ = 0.074 ± 0.001, methanol), as measured by the photo-oxidation of DMA. However, when sequestered in the nonpolar environment of a liposome, it displays strong NIR emission (λ _max = 705 nm, Ф _f = 0.087) and an extremely high singlet oxygen quantum yield (Ф_Δ→1). Of this series, H₂[pz(trans-A₂B₂)] 5a is attractive as a potential optical probe, showing strongly fluorescent uptake by cells in culture, while 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide measurements of cell viability show no evidence of dark toxicity. This agent does show significant photoinduced toxicity suggesting that pzs such as 5a have promise as “theranostic” optical agents that can be visualized with fluorescence imaging while acting as a sensitizer for photodynamic therapy.

Figure Scheme 1. Open in figure viewer PowerPoint Synthesis of Porphyrazines 3a – 7a , 3b – 7b .