The reference in the Chemical and Engineering News and The Scientist bosutinib articles to "unlicensed" bosutinib vendors is somewhat misleading, because it implies that a license from a patent owner is always required in order to legally sell a patented composition of matter. That is not correct.
The U.S. and many other countries have various exemptions from patent infringement. In the U.S., the 1984 Hatch-Waxman act granted an exemption from patent infringement claims, though it is limited to (i) drug patents only, not all patents, and (ii) uses "reasonably related to a regulatory filing" only, e.g., an FDA filing for human or veterinary use.
A U.S. Supreme Court decision in 2005 established beyond all doubt that this exemption is very broad indeed. http://www.law.cornell.edu/supct/pdf/03-1237P.ZS.
For example, use of a patented drug compound is exempt from infringement claims even if it is used merely as an internal standard for HPLC or other analyses of some other compound that is reasonably likely to be the subject of a regulatory filing.
Also, under this Supreme Court decision, the use of a patented compound to do research related to a therapeutic target site, mechanism of action, screening of compound libraries against panels of therapeutic or toxicity assays, and other lines of inquiry are exempt as long as the work is "reasonably related to a regulatory filing", prospective or actual. There is no requirement that a regulatory filing actually ever be made.
Some other countries have even broader exemptions. In Germany, it appears that the sale and use of any and all patented materials (not just drugs) to obtain information, as opposed to selling ("make, have made, use or sell") for its patent-related use, is exempt from infringement claims.
Specific references for exemptions from patent infringement in various countries include:
(i) 35 USC 271(e)+A13(1) in the U.S.;
(ii) Section 69.1 of Japanese Patent Law in Japan;
(iii) Section 11, No. 2 of the German Patent Act of 1981 in Germany;
(iv) Section 60, Paragraph 5b of the U.K. Patents Act of 1977 in the U.K.;
(v) Sections 55.2(1) and 55.2(6) and other common law exemptions of Canadian patent law;
(vi) Section 68B of the Patents Act of 1953 in New Zealand, together with the amendment of same by the Statutes Amendment Bill of 2002;
(vii) related legislation and/or case law that may be or become applicable in the aforementioned countries; and
(viii) similar laws and rules that may apply in various other countries.