Hatu

Hatu is a village in Padise Parish, Harju County in northern Estonia.

Hatu Manor

The manorial estate of Hatu (German: Hattoküll) dates from 1609, but the main building which can be seen today is much later, built only in 1864. It is constructed in an eclectic style and contains some original features in neo-Gothic and classical style, such as tiled stoves and doors. The property belonged to the Baltic German families of Mohrenschildt and Ramm. The last owner before the Estonian Declaration of Independence and the ensuing land reforms was Fridolf Gustav-Adolf von Ramm.

References

HATU

HATU (1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate) is a reagent used in peptide coupling chemistry to generate an active ester from a carboxylic acid. HATU is used along with Hünig's base (N,N-diisopropylethylamine, DIPEA) to form amide bonds. Generally DMF is used as solvent, although other polar organic solvents can also be used.

History

HATU was first reported by Louis A. Carpino in 1993 as an efficient means of preparing active esters derived from 1-hydroxy-7-azabenzotriazole (HOAt). HATU can exist as either the uronium salt (O-form) or the less reactive iminium salt (N-form). HATU was initially reported as the O-form (1) using the original preparation reported by Carpino; however, X-ray crystallographic and NMR studies revealed the true structure of HATU to be the less reactive guanidinium isomer (2). It is, however, possible to obtain the uronium isomer by preparing HATU using KOAt in place of HOAt and working up the reaction mixture quickly to prevent isomerisation.