CHEMICAL STRUCTURE

Conserved structure

	R1	R2	R3	R4	Origin
Tetracycline	H	CH3	OH	H	S. texas
Chlortetracycline	Cl	CH3	OH	H	S. aureofasciens
Oxytetracycline	H	CH3	OH	H	S. rimosus
Minocycline	N(CH3)2	H	H	H	Derivative
Doxycycline	H	CH3	H	OH	Derivative