in order to teach, he required either a master's degree from a russian university, or a ph.d. from a foreign university, so he wrote up his work on the sulfoxides and submitted it to the university of leipzig where (probably thanks to kolbe's influence) he was awarded the ph.d. in 1866. with zaytsev now holding the ph.d., butlerov was able to secure his appointment as an assistant in agronomy. (in march 1866 the kazan university board voted for this appointment.) two years later, zaytsev was awarded his m. chem. degree, and, the following year (1869) was appointed as extraordinary professor of chemistry, the junior colleague of another butlerov student, vladimir vasilyevich markovnikov (1838–1904). zaytsev submitted his dr. chem. dissertation in 1870, and was awarded the degree over the indirect objections of markovnikov (as second examiner of the dissertation, markovnikov had written an overtly positive assessment that was meant to be read between the lines). the same year, he was promoted to ordinary professor of chemistry. this may have been one of the final straws for markovnikov, who left kazan university in 1871 for odessa. zaytsev continued at kazan university until his death in 1910.