As per our interest to develop better protocols for the synthesis of biologically active heterocyclic molecules, we would like to report the synthesis of a series of new 3,4-dihydro-3-substituted-2H-naphtho[2,1-e][1,3] oxazine derivatives using 2 naphthol, formalin and various anilines as substrates in presence of Potassium Dihydrogen
In 2002, radio hosts in Kansas City created panic among listeners by reporting that local tap water contained high levels of dihydrogen
1 Fears flow over dihydrogen
monoxide -- aka "water"
You might counter the "why not" with: Because those frozen potatoes have additives such as disodium dihydrogen
(sodium acid) pyrophosphate.
Cisa, made in European Union), Dichloromethane HPLC grade (M.W 84.93, Assay 99.8%, Koch-Light Ltd., England), Methanol HPLC/Spectro Grade (M.W 32.0, Assay 99.9%, MP Biomedicals, LLC, France), Acetonitrile HPLC/Spectro Grade (M.W 41.1, Assay 99.9%, MP Biomedicals, LLC, France), Potassium dihydrogen
phosphate (98100.5%, Riedel de haen, RdH Laborchemikalion GmbH & Co.), HPLC grade Water, Distilled water
The phosphate used in this system is potassium dihydrogen
phosphate, sodium dihydrogen
phosphate, or ammonium dihydrogen
phosphate, hydrochloric acid, and sodium hydroxide were of analytical grade and obtained from Beijing Chemical Factory (Beijing, China); acetonitrile was HPLC-grade and obtained from Fisher (Leicestershire, UK).
Phosphate salts, such as ammonium dihydrogen
phosphate (N[H.sub.4][H.sub.2]P[O.sub.4]), potassium dihydrogen
phosphate (K[H.sub.2]P[O.sub.4]), and sodium dihydrogen
phosphate (Na[H.sub.2]P[O.sub.4]), were usually used to prepare MPC [10, 11].
phosphate (K[H.sub.2]P[O.sub.4], [greater than or equal to]0.995 mass fraction) and potassium nitrate (KN[O.sub.3], [greater than or equal to]0.995 mass fraction) are from Tianjin Bodi Chemical Holding Co., Ltd., China.
orthophosphate (KH2PO4) analytical, sodium hydroxide (NaOH) analytical, and methanol was purchased from Sigma-Aldrich (Germany).