Dimethyl sulfoxide d6

A Bruker DRX 500-MHz spectrometer equipped with BBI and QNP probes was used to record the spectra of amycobactin and kitamycobactin. The samples were dissolved in dimethyl sulfoxide-d₆ (Cambridge Isotope Laboratories, Andover, MA) and heated to 40°C for data acquisition. Structural assignments of amycobactin (Text S1) and kitamycobactin (Text S1) were made based on 1-dimensional (1D) and 2D nuclear magnetic resonance (NMR) data from ¹H, ¹³C, COSY, TOCSY, ¹H-¹³C/¹⁵N HSQC, ¹H-¹³C HMBC, and NOESY/ROESY experiments (Text S1). A Bruker Avance III HD spectrometer operating at a ¹H frequency of 700.13 MHz equipped with a cryogenically cooled triple-resonance 5-mm HCN probe was used to record the spectra of a sample of [¹³C, ¹⁵N]streptomycobactin dissolved in dimethyl sulfoxide-d₆ (Cambridge Isotope Laboratories, Andover, MA) in a sample tube, and the sample was heated to 35°C for data collection. The structure of streptomycobactin was assigned based on a series of 1D, 2D, and 3D NMR experiments using the [¹³C, ¹⁵N]streptomycobactin sample (Text S1). For the peptidyl backbone ¹³C assignments, the HNCACB and HNCOCACB experiments were optimized for fast data acquisition using parameters published by P. Schanda et al. in 2006 (33 (link)). Side-chain assignments were mapped with the (H)CCCONH and H(CCCO)NH experiments for ¹³C and ¹H assignments, respectively (Text S1).

Ertugliflozin active pharmaceutical gift sample was obtained from leading pharma organizations in Hyderabad. Reagents and chemicals used for the research were sodium hydroxide, hydrochloric acid, 30% hydrogen peroxide (analytical grades) formic acid (LCMS grade), acetonitrile (HPLC grade), procured from Honeywell Research Chemicals, India. The water used for the analysis was from a milli-Q instrument from Millipore, Amsterdam, Netherlands. Dimethylsulfoxide-d6 (NMR grade) from Cambridge Isotope Laboratories, Inc. D, 99.9% + 0.03% v/v.

All chemicals used throughout the study were of the highest quality. Methanol (>99.9% pure) was purchased from Fisher Chemical (Fair Lawn, NJ, USA). Dimethyl Sulfoxide-D₆ (DMSO, >99.5% pure) was purchased from Cambridge Isotope Laboratories, Inc. (Tewksbury, MA, USA). For confirmation of sugars, d-mannitol (>98% pure), sucrose (>99.5% pure), d-(+)-raffinose pentahydrate (>98% pure), and d-(+)-trehalose dihydrate (>99.0% pure) were purchased from Sigma-Aldrich (St Louis, MO, USA. d-glucose (>99% pure) and inositol (>98%) were purchased from Cambridge Isotope Laboratories, Inc. and d-(-)-fructose (>98% pure) was purchased from BDH Analytical (Poole, UK). Ciceritol was isolated in-house (Briefly, a water extract of chickpeas was purified by reverse phase C18 HPLC, to afford ciceritol). Two phenolic compounds, (+)-catechin hydrate (98%) and (-)-epicatechin, were purchased from Sigma-Aldrich.